485BPOS

As filed with the Securities and Exchange Commission on November 7, 2018

File Nos. 033-12988

811-05088

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933	☐
Pre-Effective Amendment No.	☐
Post-Effective Amendment No. 115	☒

and/or

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF 1940

Amendment No. 117 ☒

THE AB PORTFOLIOS

(Exact Name of Registrant as Specified in Charter)

1345 Avenue of the Americas

New York, N.Y. 10105

(Address of Principal Executive Office) (Zip Code)

(Registrant’s Telephone Number, including Area Code):

(800) 221-5672

EMILIE D. WRAPP

AllianceBernstein L.P.

1345 Avenue of the Americas

New York, N.Y. 10105

(Name and address of Agent for Service)

Copies of communications to:

Paul M. Miller

Seward & Kissel LLP

901 K Street, NW

Suite 800

Washington, DC 20001

It is proposed that this filing will become effective (check appropriate box)

☒ immediately upon filing pursuant to paragraph (b)

☐ on (date) pursuant to paragraph (b)

☐ 60 days after filing pursuant to paragraph (a)(1)

☐ on (date) pursuant to paragraph (a)(1)

☐ 75 days after filing pursuant to paragraph (a)(2)

☐ on (date) pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

☐ This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

This Post-Effective Amendment No. 115 relates solely to the Class A, Class B, Class C, Class R, Class K, Class I and Advisor Class shares of the AB Growth Fund. No information in the Registrant’s Registration Statement relating to the other Series or Classes of the Registrant not included herein is amended or superseded.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all of the requirements for effectiveness of this Amendment to its Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Amendment to its Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of New York and the State of New York, on the 7^th day of November, 2018.

THE AB PORTFOLIOS
By:	Robert M. Keith*
	Robert M. Keith President

Pursuant to the requirements of the Securities Act of l933, as amended, this Amendment to the Registration Statement has been signed below by the following persons in the capacities and on the date indicated.

	Signature	Title	Date
1)	Principal Executive Officer:
	Robert M. Keith* Robert M. Keith	President and Chief Executive Officer	November 7, 2018
2)	Principal Financial and Accounting Officer:
	/s/ Joseph J. Mantineo Joseph J. Mantineo	Treasurer and Chief Financial Officer	November 7, 2018
3)	The Trustees:
	Michael J. Downey* William H. Foulk, Jr.* Nancy P. Jacklin* Robert M. Keith* Carol C. McMullen* Garry L. Moody* Marshall C. Turner, Jr.* Earl D. Weiner*
*By:	/s/ Stephen J. Laffey Stephen J. Laffey (Attorney-in-fact)		November 7, 2018

Index to Exhibits

Exhibit No.	Description of Exhibits
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CALC	XBRL Taxonomy Extension Calculation Linkbase
EX-101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Jul. 31, 2018
Registrant Name	dei_EntityRegistrantName	AB PORTFOLIOS
Central Index Key	dei_EntityCentralIndexKey	0000812015
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Oct. 26, 2018
Document Effective Date	dei_DocumentEffectiveDate	Oct. 31, 2018
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
Entity Inv Company Type	dei_EntityInvCompanyType	N-1A

XML

AB Growth Fund

SUMMARY INFORMATION<br/><br/> AB GROWTH FUND

INVESTMENT OBJECTIVE

The Fund’s investment objective is long-term growth of capital.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in AB Mutual Funds. More information about these and other discounts is available from your financial intermediary and in Investing in the Funds--Sales Charge Reduction Programs for Class A Shares on page 66 of this Prospectus, in Appendix B--Financial Intermediary Waivers of this Prospectus and in Purchase of Shares--Sales Charge Reduction Programs for Class A Shares on page 130 of the Fund’s Statement of Additional Information (“SAI”).

You may be required to pay commissions and/or other forms of compensation to a broker for transactions in Advisor Class shares, which are not reflected in the tables or the examples below.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - AB Growth Fund	CLASS A SHARES		CLASS B SHARES		CLASS C SHARES		ADVISOR CLASS SHARES	CLASS R SHARES	CLASS K SHARES	CLASS I SHARES
Shareholder Fees Column [Text]			(NOT CURRENTLY OFFERED TO NEW INVESTORS)
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	4.25%		none		none		none	none	none	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	none	[1]	4.00%	[2]	1.00%	[3]	none	none	none	none
Exchange Fee	none		none		none		none	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage<br/>of the value of your investment)

Annual Fund Operating Expenses - AB Growth Fund		CLASS A	CLASS B	CLASS C	ADVISOR CLASS	CLASS R	CLASS K	CLASS I
Management Fees		0.75%	0.75%	0.75%	0.75%	0.75%	0.75%	0.75%
Distribution and/or Service (12b-1) Fees		0.25%	1.00%	1.00%	none	0.50%	0.25%	none
Other Expenses: Transfer Agent		0.14%	0.16%	0.14%	0.13%	0.25%	0.20%	0.02%
Other Expenses		0.06%	0.06%	0.06%	0.06%	0.06%	0.06%	0.06%
Total Other Expenses		0.20%	0.22%	0.20%	0.19%	0.31%	0.26%	0.08%
Acquired Fund Fees and Expenses		0.01%	0.01%	0.01%	0.01%	0.01%	0.01%	0.01%
Total Annual Fund Operating Expenses		1.21%	1.98%	1.96%	0.95%	1.57%	1.27%	0.84%
Fee Waiver and/or Expense Reimbursement	[1]	(0.01%)	(0.01%)	(0.01%)	(0.01%)	(0.01%)	(0.01%)	(0.01%)
Total Annual Fund Operating Expenses After Fee Wavier and/or Expense Reimbursement		1.20%	1.97%	1.95%	0.94%	1.56%	1.26%	0.83%

EXAMPLES

The Examples are intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Examples assume that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Examples also assume that your investment has a 5% return each year, that the Fund’s operating expenses stay the same and that any fee waiver remains in effect for only the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - AB Growth Fund - USD ($)	CLASS A	CLASS B	CLASS C	ADVISOR CLASS	CLASS R	CLASS K	CLASS I
After 1 Year	$ 542	$ 600	$ 298	$ 96	$ 159	$ 128	$ 85
After 3 Years	792	820	614	302	495	402	267
After 5 Years	1,061	1,067	1,056	525	854	696	465
After 10 Years	$ 1,828	$ 2,106	$ 2,284	$ 1,165	$ 1,867	$ 1,533	$ 1,036

For the share classes listed below, you would pay the following expenses if you did not redeem your shares at the end of the period.

Expense Example, No Redemption - AB Growth Fund - USD ($)	CLASS B	CLASS C
After 1 Year	$ 200	$ 198
After 3 Years	620	614
After 5 Years	1,067	1,056
After 10 Years	$ 2,106	$ 2,284

PORTFOLIO TURNOVER

The Fund pays transaction costs, such as commissions, when it buys or sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These transaction costs, which are not reflected in the Annual Fund Operating Expenses or in the Examples, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 46% of the average value of its portfolio.

PRINCIPAL STRATEGIES

The Fund invests primarily in a domestic portfolio of equity securities of companies selected by the Fund's Adviser for their growth potential within various market sectors. When selecting securities, the Adviser looks for companies that have experienced management teams, strong market positions, and the potential to deliver greater-than-expected earnings growth rates.

In managing the Fund, the Adviser allocates investments among broad sector groups and selects specific investments based on the fundamental company research conducted by the Adviser's internal research staff, assessing the current and forecasted investment opportunities and conditions, as well as diversification and risk considerations. The Adviser's research focus is on companies with high sustainable growth prospects, high or improving return on invested capital, transparent business models, and clear competitive advantages.

The Fund has the flexibility to invest across the capitalization spectrum. The Fund is designed for those seeking exposure to companies of various sizes, and typically has substantial investments in both large-capitalization companies and mid-capitalization companies, and may also invest in small-capitalization companies.

The Fund may enter into derivatives transactions, such as options, futures contracts, forwards and swaps. The Fund may use options strategies involving the purchase and/or writing of various combinations of call and/or put options, including on individual securities and stock indices, futures contracts (including futures contracts on individual securities and stock indices) or shares of exchange-traded funds ("ETFs"). These transactions may be used, for example, in an effort to earn extra income, to adjust exposure to individual securities or markets, or to protect all or a portion of the Fund's portfolio from a decline in value.

PRINCIPAL RISKS

• MARKET RISK: The value of the Fund’s assets will fluctuate as the stock or bond market fluctuates. The value of its investments may decline, sometimes rapidly and unpredictably, simply because of economic changes or other events that affect large portions of the market. It includes the risk that a particular style of investing, such as growth, may underperform the market generally.

• FOCUSED PORTFOLIO RISK: Investments in a limited number of companies may have more risk because changes in the value of a single security may have a more significant effect, either negative or positive, on the Fund’s net asset value, or NAV.

• SECTOR RISK: The Fund may have more risk because of concentrated investments in a particular market sector, such as the technology or financial services sector. Market or economic factors affecting that sector could have a major effect on the value of the Fund’s investments.

• CAPITALIZATION RISK: Investments in small- and mid-capitalization companies may be more volatile than investments in large-capitalization companies. Investments in small-capitalization companies may have additional risks because these companies have limited product lines, markets or financial resources.

• DERIVATIVES RISK: Derivatives may be illiquid, difficult to price, and leveraged so that small changes may produce disproportionate losses for the Fund, and may be subject to counterparty risk to a greater degree than more traditional investments.

• MANAGEMENT RISK: The Fund is subject to management risk because it is an actively-managed investment fund. The Adviser will apply its investment techniques and risk analyses in making investment decisions for the Fund, but there is no guarantee that its techniques will produce the intended results.

As with all investments, you may lose money by investing in the Fund.

BAR CHART AND PERFORMANCE INFORMATION

The bar chart and performance information provide an indication of the historical risk of an investment in the Fund by showing:

• how the Fund's performance changed from year to year over ten years; and

• how the Fund's average annual returns for one, five and ten years compare to those of a broad-based securities market index.

You may obtain updated performance information on the Fund's website at www.abfunds.com (click on "Investments--Mutual Funds").

The Fund's past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.

BAR CHART

The annual returns in the bar chart are for the Fund's Class A shares and do not reflect sales loads. If sales loads were reflected, returns would be less than those shown. Through September 30, 2018, the year-to-date unannualized return for Class A shares was 18.67%.

During the period shown in the bar chart, the Fund's:

BEST QUARTER WAS UP 15.47%, 1ST QUARTER, 2012; AND WORST QUARTER WAS DOWN
-22.97%, 4TH QUARTER, 2008.

PERFORMANCE TABLE<br/>AVERAGE ANNUAL TOTAL RETURNS<br/><br/>(For the periods ended December 31, 2017)

Average Annual Total Returns - AB Growth Fund		1 YEAR	5 YEARS	10 YEARS
CLASS A	[1],[2]	28.15%	16.33%	7.93%
CLASS A | Return After Taxes on Distributions	[1],[2]	25.54%	15.05%	7.33%
CLASS A | Return After Taxes on Distributions and Sale of Fund Shares	[1],[2]	18.07%	13.04%	6.38%
CLASS B	[2]	28.81%	16.42%	7.70%
CLASS C	[2]	31.84%	16.47%	7.60%
ADVISOR CLASS	[2]	34.19%	17.66%	8.71%
CLASS R	[2]	33.37%	17.02%	8.20%
CLASS K	[2]	33.79%	17.39%	8.55%
CLASS I	[2]	34.37%	17.81%	8.91%
Russell 3000(R) Growth Index (reflects no deduction for fees, expenses, or taxes)	[2]	29.59%	17.16%	9.93%

[1] Purchases of Class A shares in amounts of $1,000,000 or more, or by certain group retirement plans, may be subject to a 1%, 1-year contingent deferred sales charge, or CDSC, which may be subject to waiver in certain circumstances.

[2] Class B shares automatically convert to Class A shares after eight years. The CDSC decreases over time. For Class B shares, the CDSC decreases 1.00% annually to 0% after the fourth year.

[3] For Class C shares, the CDSC is 0% after the first year. Class C shares automatically convert to Class A shares after ten years.

[1] In connection with the Fund's investments in AB Government Money Market Portfolio (the "Money Market Portfolio"), the Adviser has contractually agreed to waive its management fee from the Fund and/or reimburse other expenses of the Fund in an amount equal to the Fund's pro rata share of the Money Market Portfolio's effective management fee, as included in "Acquired Fund Fees and Expenses".

[1] After-tax returns: -Are shown for Class A shares only and will vary for the other Classes of shares because these Classes have different expense ratios; -Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes; actual after-tax returns depend on an individual investor's tax situation and are likely to differ from those shown; and -Are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

[2] Includes the impact of proceeds of a distribution on November 2, 2017 and November 17, 2017 relating to regulatory settlements, which enhanced the performance of all share classes of the Fund for the 1-Year period ended December 31, 2017, by 0.05% and 0.09%, respectively.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	AB PORTFOLIOS
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
AB Growth Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY INFORMATION<br/><br/> AB GROWTH FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund’s investment objective is long-term growth of capital.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in AB Mutual Funds. More information about these and other discounts is available from your financial intermediary and in Investing in the Funds--Sales Charge Reduction Programs for Class A Shares on page 66 of this Prospectus, in Appendix B--Financial Intermediary Waivers of this Prospectus and in Purchase of Shares--Sales Charge Reduction Programs for Class A Shares on page 130 of the Fund’s Statement of Additional Information (“SAI”). You may be required to pay commissions and/or other forms of compensation to a broker for transactions in Advisor Class shares, which are not reflected in the tables or the examples below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	SHAREHOLDER FEES (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage<br/>of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys or sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These transaction costs, which are not reflected in the Annual Fund Operating Expenses or in the Examples, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 46% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	46.00%
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	Purchases of Class A shares in amounts of $1,000,000 or more, or by certain group retirement plans, may be subject to a 1%, 1-year contingent deferred sales charge, or CDSC, which may be subject to waiver in certain circumstances. Class B shares automatically convert to Class A shares after eight years. The CDSC decreases over time. For Class B shares, the CDSC decreases 1.00% annually to 0% after the fourth year. For Class C shares, the CDSC is 0% after the first year. Class C shares automatically convert to Class A shares after ten years.
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in AB Mutual Funds.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 100,000
Expense Example [Heading]	rr_ExpenseExampleHeading	EXAMPLES
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The Examples are intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Examples assume that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Examples also assume that your investment has a 5% return each year, that the Fund’s operating expenses stay the same and that any fee waiver remains in effect for only the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	For the share classes listed below, you would pay the following expenses if you did not redeem your shares at the end of the period.
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund invests primarily in a domestic portfolio of equity securities of companies selected by the Fund's Adviser for their growth potential within various market sectors. When selecting securities, the Adviser looks for companies that have experienced management teams, strong market positions, and the potential to deliver greater-than-expected earnings growth rates. In managing the Fund, the Adviser allocates investments among broad sector groups and selects specific investments based on the fundamental company research conducted by the Adviser's internal research staff, assessing the current and forecasted investment opportunities and conditions, as well as diversification and risk considerations. The Adviser's research focus is on companies with high sustainable growth prospects, high or improving return on invested capital, transparent business models, and clear competitive advantages. The Fund has the flexibility to invest across the capitalization spectrum. The Fund is designed for those seeking exposure to companies of various sizes, and typically has substantial investments in both large-capitalization companies and mid-capitalization companies, and may also invest in small-capitalization companies. The Fund may enter into derivatives transactions, such as options, futures contracts, forwards and swaps. The Fund may use options strategies involving the purchase and/or writing of various combinations of call and/or put options, including on individual securities and stock indices, futures contracts (including futures contracts on individual securities and stock indices) or shares of exchange-traded funds ("ETFs"). These transactions may be used, for example, in an effort to earn extra income, to adjust exposure to individual securities or markets, or to protect all or a portion of the Fund's portfolio from a decline in value.
Risk [Heading]	rr_RiskHeading	PRINCIPAL RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	MARKET RISK: The value of the Fund’s assets will fluctuate as the stock or bond market fluctuates. The value of its investments may decline, sometimes rapidly and unpredictably, simply because of economic changes or other events that affect large portions of the market. It includes the risk that a particular style of investing, such as growth, may underperform the market generally. FOCUSED PORTFOLIO RISK: Investments in a limited number of companies may have more risk because changes in the value of a single security may have a more significant effect, either negative or positive, on the Fund’s net asset value, or NAV. SECTOR RISK: The Fund may have more risk because of concentrated investments in a particular market sector, such as the technology or financial services sector. Market or economic factors affecting that sector could have a major effect on the value of the Fund’s investments. CAPITALIZATION RISK: Investments in small- and mid-capitalization companies may be more volatile than investments in large-capitalization companies. Investments in small-capitalization companies may have additional risks because these companies have limited product lines, markets or financial resources. DERIVATIVES RISK: Derivatives may be illiquid, difficult to price, and leveraged so that small changes may produce disproportionate losses for the Fund, and may be subject to counterparty risk to a greater degree than more traditional investments. MANAGEMENT RISK: The Fund is subject to management risk because it is an actively-managed investment fund. The Adviser will apply its investment techniques and risk analyses in making investment decisions for the Fund, but there is no guarantee that its techniques will produce the intended results. As with all investments, you may lose money by investing in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, you may lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	BAR CHART AND PERFORMANCE INFORMATION
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and performance information provide an indication of the historical risk of an investment in the Fund by showing: how the Fund's performance changed from year to year over ten years; and how the Fund's average annual returns for one, five and ten years compare to those of a broad-based securities market index. You may obtain updated performance information on the Fund's website at www.abfunds.com (click on "Investments--Mutual Funds"). The Fund's past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<ul><li type="square">how the Fund's performance changed from year to year over ten years; and</li></ul><ul><li type="square">how the Fund's average annual returns for one, five and ten years compare to those of a broad-based securities market index.</li></ul>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.abfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	BAR CHART
Bar Chart Narrative [Text Block]	rr_BarChartNarrativeTextBlock	The annual returns in the bar chart are for the Fund's Class A shares and do not reflect sales loads. If sales loads were reflected, returns would be less than those shown. Through September 30, 2018, the year-to-date unannualized return for Class A shares was 18.67%.
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	The annual returns in the bar chart are for the Fund's Class A shares and do not reflect sales loads. If sales loads were reflected, returns would be less than those shown.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the Fund's: BEST QUARTER WAS UP 15.47%, 1ST QUARTER, 2012; AND WORST QUARTER WAS DOWN -22.97%, 4TH QUARTER, 2008.
Performance Table Heading	rr_PerformanceTableHeading	PERFORMANCE TABLE<br/>AVERAGE ANNUAL TOTAL RETURNS<br/><br/>(For the periods ended December 31, 2017)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns: -Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes;
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	actual after-tax returns depend on an individual investor's tax situation and are likely to differ from those shown; and -Are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns: -Are shown for Class A shares only and will vary for the other Classes of shares because these Classes have different expense ratios;
AB Growth Fund | CLASS A
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	4.25%
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none	[1]
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.14%
Other Expenses	rr_Component2OtherExpensesOverAssets	0.06%
Total Other Expenses	rr_OtherExpensesOverAssets	0.20%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.21%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[2]
Total Annual Fund Operating Expenses After Fee Wavier and/or Expense Reimbursement	rr_NetExpensesOverAssets	1.20%
After 1 Year	rr_ExpenseExampleYear01	$ 542
After 3 Years	rr_ExpenseExampleYear03	792
After 5 Years	rr_ExpenseExampleYear05	1,061
After 10 Years	rr_ExpenseExampleYear10	$ 1,828
2008	rr_AnnualReturn2008	(43.38%)
2009	rr_AnnualReturn2009	35.05%
2010	rr_AnnualReturn2010	14.95%
2011	rr_AnnualReturn2011	1.04%
2012	rr_AnnualReturn2012	13.34%
2013	rr_AnnualReturn2013	33.41%
2014	rr_AnnualReturn2014	12.89%
2015	rr_AnnualReturn2015	8.81%
2016	rr_AnnualReturn2016	1.46%
2017	rr_AnnualReturn2017	33.83%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	18.67%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	BEST QUARTER
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2012
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	15.47%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	WORST QUARTER
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(22.97%)
1 YEAR	rr_AverageAnnualReturnYear01	28.15%	[3],[4]
5 YEARS	rr_AverageAnnualReturnYear05	16.33%	[3],[4]
10 YEARS	rr_AverageAnnualReturnYear10	7.93%	[3],[4]
AB Growth Fund | CLASS B
Risk/Return:	rr_RiskReturnAbstract
Shareholder Fees Column [Text]	rr_ShareholderFeesColumnName	(NOT CURRENTLY OFFERED TO NEW INVESTORS)
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	4.00%	[5]
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.16%
Other Expenses	rr_Component2OtherExpensesOverAssets	0.06%
Total Other Expenses	rr_OtherExpensesOverAssets	0.22%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.98%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[2]
Total Annual Fund Operating Expenses After Fee Wavier and/or Expense Reimbursement	rr_NetExpensesOverAssets	1.97%
After 1 Year	rr_ExpenseExampleYear01	$ 600
After 3 Years	rr_ExpenseExampleYear03	820
After 5 Years	rr_ExpenseExampleYear05	1,067
After 10 Years	rr_ExpenseExampleYear10	2,106
After 1 Year	rr_ExpenseExampleNoRedemptionYear01	200
After 3 Years	rr_ExpenseExampleNoRedemptionYear03	620
After 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,067
After 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,106
1 YEAR	rr_AverageAnnualReturnYear01	28.81%	[4]
5 YEARS	rr_AverageAnnualReturnYear05	16.42%	[4]
10 YEARS	rr_AverageAnnualReturnYear10	7.70%	[4]
AB Growth Fund | CLASS C
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[6]
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.14%
Other Expenses	rr_Component2OtherExpensesOverAssets	0.06%
Total Other Expenses	rr_OtherExpensesOverAssets	0.20%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.96%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[2]
Total Annual Fund Operating Expenses After Fee Wavier and/or Expense Reimbursement	rr_NetExpensesOverAssets	1.95%
After 1 Year	rr_ExpenseExampleYear01	$ 298
After 3 Years	rr_ExpenseExampleYear03	614
After 5 Years	rr_ExpenseExampleYear05	1,056
After 10 Years	rr_ExpenseExampleYear10	2,284
After 1 Year	rr_ExpenseExampleNoRedemptionYear01	198
After 3 Years	rr_ExpenseExampleNoRedemptionYear03	614
After 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,056
After 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,284
1 YEAR	rr_AverageAnnualReturnYear01	31.84%	[4]
5 YEARS	rr_AverageAnnualReturnYear05	16.47%	[4]
10 YEARS	rr_AverageAnnualReturnYear10	7.60%	[4]
AB Growth Fund | ADVISOR CLASS
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.13%
Other Expenses	rr_Component2OtherExpensesOverAssets	0.06%
Total Other Expenses	rr_OtherExpensesOverAssets	0.19%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.95%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[2]
Total Annual Fund Operating Expenses After Fee Wavier and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.94%
After 1 Year	rr_ExpenseExampleYear01	$ 96
After 3 Years	rr_ExpenseExampleYear03	302
After 5 Years	rr_ExpenseExampleYear05	525
After 10 Years	rr_ExpenseExampleYear10	$ 1,165
1 YEAR	rr_AverageAnnualReturnYear01	34.19%	[4]
5 YEARS	rr_AverageAnnualReturnYear05	17.66%	[4]
10 YEARS	rr_AverageAnnualReturnYear10	8.71%	[4]
AB Growth Fund | CLASS R
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.25%
Other Expenses	rr_Component2OtherExpensesOverAssets	0.06%
Total Other Expenses	rr_OtherExpensesOverAssets	0.31%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.57%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[2]
Total Annual Fund Operating Expenses After Fee Wavier and/or Expense Reimbursement	rr_NetExpensesOverAssets	1.56%
After 1 Year	rr_ExpenseExampleYear01	$ 159
After 3 Years	rr_ExpenseExampleYear03	495
After 5 Years	rr_ExpenseExampleYear05	854
After 10 Years	rr_ExpenseExampleYear10	$ 1,867
1 YEAR	rr_AverageAnnualReturnYear01	33.37%	[4]
5 YEARS	rr_AverageAnnualReturnYear05	17.02%	[4]
10 YEARS	rr_AverageAnnualReturnYear10	8.20%	[4]
AB Growth Fund | CLASS K
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.20%
Other Expenses	rr_Component2OtherExpensesOverAssets	0.06%
Total Other Expenses	rr_OtherExpensesOverAssets	0.26%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.27%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[2]
Total Annual Fund Operating Expenses After Fee Wavier and/or Expense Reimbursement	rr_NetExpensesOverAssets	1.26%
After 1 Year	rr_ExpenseExampleYear01	$ 128
After 3 Years	rr_ExpenseExampleYear03	402
After 5 Years	rr_ExpenseExampleYear05	696
After 10 Years	rr_ExpenseExampleYear10	$ 1,533
1 YEAR	rr_AverageAnnualReturnYear01	33.79%	[4]
5 YEARS	rr_AverageAnnualReturnYear05	17.39%	[4]
10 YEARS	rr_AverageAnnualReturnYear10	8.55%	[4]
AB Growth Fund | CLASS I
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.02%
Other Expenses	rr_Component2OtherExpensesOverAssets	0.06%
Total Other Expenses	rr_OtherExpensesOverAssets	0.08%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.84%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[2]
Total Annual Fund Operating Expenses After Fee Wavier and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.83%
After 1 Year	rr_ExpenseExampleYear01	$ 85
After 3 Years	rr_ExpenseExampleYear03	267
After 5 Years	rr_ExpenseExampleYear05	465
After 10 Years	rr_ExpenseExampleYear10	$ 1,036
1 YEAR	rr_AverageAnnualReturnYear01	34.37%	[4]
5 YEARS	rr_AverageAnnualReturnYear05	17.81%	[4]
10 YEARS	rr_AverageAnnualReturnYear10	8.91%	[4]
AB Growth Fund | Return After Taxes on Distributions | CLASS A
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	25.54%	[3],[4]
5 YEARS	rr_AverageAnnualReturnYear05	15.05%	[3],[4]
10 YEARS	rr_AverageAnnualReturnYear10	7.33%	[3],[4]
AB Growth Fund | Return After Taxes on Distributions and Sale of Fund Shares | CLASS A
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	18.07%	[3],[4]
5 YEARS	rr_AverageAnnualReturnYear05	13.04%	[3],[4]
10 YEARS	rr_AverageAnnualReturnYear10	6.38%	[3],[4]
AB Growth Fund | Russell 3000(R) Growth Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	29.59%	[4]
5 YEARS	rr_AverageAnnualReturnYear05	17.16%	[4]
10 YEARS	rr_AverageAnnualReturnYear10	9.93%	[4]

[1] Purchases of Class A shares in amounts of $1,000,000 or more, or by certain group retirement plans, may be subject to a 1%, 1-year contingent deferred sales charge, or CDSC, which may be subject to waiver in certain circumstances.

[2] In connection with the Fund's investments in AB Government Money Market Portfolio (the "Money Market Portfolio"), the Adviser has contractually agreed to waive its management fee from the Fund and/or reimburse other expenses of the Fund in an amount equal to the Fund's pro rata share of the Money Market Portfolio's effective management fee, as included in "Acquired Fund Fees and Expenses".

[3] After-tax returns: -Are shown for Class A shares only and will vary for the other Classes of shares because these Classes have different expense ratios; -Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes; actual after-tax returns depend on an individual investor's tax situation and are likely to differ from those shown; and -Are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

[4] Includes the impact of proceeds of a distribution on November 2, 2017 and November 17, 2017 relating to regulatory settlements, which enhanced the performance of all share classes of the Fund for the 1-Year period ended December 31, 2017, by 0.05% and 0.09%, respectively.

[5] Class B shares automatically convert to Class A shares after eight years. The CDSC decreases over time. For Class B shares, the CDSC decreases 1.00% annually to 0% after the fourth year.

[6] For Class C shares, the CDSC is 0% after the first year. Class C shares automatically convert to Class A shares after ten years.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	AB PORTFOLIOS
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
Document Creation Date	dei_DocumentCreationDate	Oct. 26, 2018