Morgan Stanley Institutional Fund, Inc.

International Equity Portfolio

Summary Prospectus | April 30, 2018


Share Class and Ticker Symbols
Class I	Class A	Class L	Class C	Class IS
MSIQX	MIQBX	MSQLX	MSECX	MIQPX

Before you invest, you may want to review the Fund’s statutory prospectus (“Prospectus”), which contains more information about the Fund and its risks. You can find the Fund’s Prospectus and other information about the Fund, including the Statement of Additional Information (“SAI”) and the most recent annual and semiannual reports to shareholders, online at www.morganstanley.com/im. You can also get this information at no cost by calling toll-free 1-866-414-6349 or by sending an e-mail request to orders@mysummaryprospectus.com. The Fund’s Prospectus and SAI, both dated April 30, 2018 (as may be supplemented from time to time), are incorporated by reference into this Summary Prospectus.

Investment Objective

The International Equity Portfolio (the “Fund”) seeks long-term capital appreciation by investing primarily in equity securities of non-U.S. issuers.

Fees and Expenses

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund. For purchases of Class A shares, you may qualify for a sales charge discount if the cumulative net asset value per share (“NAV”) of Class A shares of the Fund being purchased in a single transaction, together with the NAV of any Class A, Class L and Class C shares of the Fund already held in Related Accounts (as defined in the section of the Prospectus entitled “Shareholder Information—Sales Charges Applicable to Purchases of Class A Shares”) as of the date of the transaction as well as Class A, Class B, Class L and Class C shares of any other Morgan Stanley Multi-Class Fund (as defined in the section of the Prospectus entitled “Shareholder Information—Exchange Privilege”) and including shares of Morgan Stanley Money Market Funds (as defined in the section of the Prospectus entitled “Shareholder Information—Exchange Privilege”) that you acquired in an exchange from Class A shares of the Fund or Class A shares of

another Morgan Stanley Multi-Class Fund already held in Related Accounts as of the date of the transaction, amounts to $25,000 or more. More information about this combined purchase discount and other discounts is available from your authorized financial intermediary, on page 76 of the Prospectus in the section entitled “Shareholder Information—Sales Charges Applicable to Purchases of Class A Shares” and in Appendix A attached to the Prospectus.

Shareholder Fees (fees paid directly from your investment)


	Class I	Class A	Class L	Class C	Class IS
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	None	5.25%	None	None	None
Maximum deferred sales charge (load) (as a percentage based on the lesser of the offering price or NAV at redemption)	None	None¹	None	1.00%²	None
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%	2.00%	2.00%	2.00%	2.00%

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)


	Class I	Class A	Class L	Class C	Class IS
Advisory Fee	0.80%	0.80%	0.80%	0.80%	0.80%
Distribution and/or Shareholder Service (12b-1) Fee	None	0.25%	0.75%	1.00%	None
Other Expenses	0.19%	0.26%	0.35%	0.61%	0.11%
Total Annual FundOperating Expenses³	0.99%	1.31%	1.90%	2.41%	0.91%
Fee Waiver and/or Expense Reimbursement³	0.04%	0.01%	0.10%	0.36%	0.00%

Morgan Stanley Institutional Fund, Inc. Prospectus | Fund Summary

International Equity Portfolio (Con’t)


	Class I	Class A	Class L	Class C	Class IS
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement³	0.95%	1.30%	1.80%	2.05%	0.91%

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The example assumes that you invest $10,000 in the Fund, your investment has a 5% return each year and the Fund’s operating expenses remain the same (except that the example incorporates the fee waiver and/or expense reimbursement arrangement for only the first year). Although your actual costs may be higher or lower, based on these assumptions your costs would be:


If You SOLD Your Shares
	1 Year	3 Years	5 Years	10 Years
Class I	$ 97	$ 311	$ 543	$ 1,209
Class A	$ 650	$ 917	$ 1,205	$ 2,020
Class L	$ 183	$ 587	$ 1,017	$ 2,214
Class C	$ 308	$ 717	$ 1,253	$ 2,719
Class IS	$ 93	$ 290	$ 504	$ 1,120


If You HELD Your Shares
	1 Year	3 Years	5 Years	10 Years
Class I	$ 97	$ 311	$ 543	$ 1,209
Class A	$ 650	$ 917	$ 1,205	$ 2,020
Class L	$ 183	$ 587	$ 1,017	$ 2,214
Class C	$ 208	$ 717	$ 1,253	$ 2,719
Class IS	$ 93	$ 290	$ 504	$ 1,120

Investments in Class A shares that are not subject to any sales charges at the time of purchase are subject to a contingent deferred sales charge (“CDSC”) of 1.00% that will be imposed if you sell your shares within 18 months after the last day of the month of purchase, except for certain specific circumstances. See “Shareholder Information—How to Redeem Fund Shares” for further information about the CDSC waiver categories.

2	The Class C CDSC is only applicable if you sell your shares within one year after purchase. See “Shareholder Information—How to Redeem Fund Shares” for a complete discussion of the CDSC.

The Fund’s “Adviser,” Morgan Stanley Investment Management Inc., has agreed to reduce its advisory fee and/or reimburse the Fund so that Total Annual Fund Operating Expenses, excluding certain investment related expenses, taxes, interest and other extraordinary expenses (including litigation), will not exceed 0.95% for Class I, 1.30% for Class A, 1.80% for Class L, 2.05% for Class C and 0.91% for Class IS. The fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Board of Directors of Morgan Stanley Institutional Fund, Inc. (the “Company”) acts to discontinue all or a portion of such waivers and/or reimbursements when it deems such action is appropriate.

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and 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 costs, which are not reflected in Total

Annual Fund Operating Expenses or in the Example, affect Fund performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 18% of the average value of its portfolio.

Principal Investment Strategies

The Adviser and the Fund’s “Sub-Adviser,” Morgan Stanley Investment Management Limited (“MSIM Limited”), seek long-term capital appreciation by investing in a diversified portfolio of equity securities of non-U.S. issuers based on fundamental analysis and individual stock selection.

Utilizing a bottom-up approach to investing, the Adviser and/or Sub-Adviser look to invest in two types of stocks: attractively priced high quality compounders, companies characterized by their ability to generate sustainably high returns on capital, and value opportunities, which are more cyclical companies with reasonable or improving fundamentals trading at a sufficient discount to intrinsic value.

The Adviser and/or Sub-Adviser conduct in-depth fundamental research on a company by company basis, including close examination of each company’s franchise, management and financial characteristics, and consider value criteria with an emphasis on cash flow-based-metrics rather than accounting numbers to assess intrinsic value. The Adviser and/or Sub-Adviser also seek experienced company management teams that have a history of disciplined capital allocation.

The Adviser and/or Sub-Adviser believe that a portfolio consisting of both types of stocks, with the flexibility to adjust the mix dependent on company valuation and prospects, has the potential to generate attractive long-term returns for investors.

The Fund’s investment process focuses on the sustainability and direction of a company’s long term returns on capital. Environmental, social and governance (ESG) considerations are a fundamental and integrated part of this process, as the Adviser and/or Sub-Adviser believe material weaknesses in any of the ESG areas can potentially threaten the long-term sustainability of a company’s returns on capital.

Under normal circumstances, at least 80% of the Fund’s assets will be invested in equity securities. This policy may be changed without shareholder approval; however, you would be notified upon 60 days’ notice in writing of any changes. The Fund’s equity investments may include convertible securities.

The Fund may, but it is not required to, use derivative instruments for a variety of purposes, including hedging, risk management, portfolio management or to earn income. The Fund’s use of derivatives may involve the purchase and sale of derivative instruments such as futures, options, swaps, contracts for difference (“CFDs”) and other related instruments and techniques. The Fund may utilize foreign currency forward exchange contracts, which are also derivatives, in connection with its investments in foreign securities. Derivative instruments used by the Fund will be counted toward the Fund’s 80% policy discussed above to the extent they have economic characteristics similar to the securities included within that policy.

Morgan Stanley Institutional Fund, Inc. Prospectus | Fund Summary

International Equity Portfolio (Con’t)

Principal Risks

There is no assurance that the Fund will achieve its investment objective, and you can lose money investing in this Fund. The principal risks of investing in the Fund include:

•

Equity Securities. In general, prices of equity securities are more volatile than those of fixed income securities. The prices of equity securities fluctuate, and sometimes widely fluctuate, in response to activities specific to the issuer of the security as well as factors unrelated to the fundamental condition of the issuer, including general market, economic and political conditions. To the extent that the Fund invests in convertible securities, and the convertible security’s investment value is greater than its conversion value, its price will be likely to increase when interest rates fall and decrease when interest rates rise. If the conversion value exceeds the investment value, the price of the convertible security will tend to fluctuate directly with the price of the underlying security.

•

Small and Medium Capitalization Companies. Investments in small and medium capitalization companies may involve greater risks than investments in larger, more established companies. The securities issued by small and medium capitalization companies may be less liquid and such companies may have more limited markets, financial resources and product lines, and may lack the depth of management of larger companies.

•

Foreign and Emerging Market Securities. Investments in foreign markets entail special risks such as currency, political, economic and market risks. There also may be greater market volatility, less reliable financial information, higher transaction and custody costs, decreased market liquidity and less government and exchange regulation associated with investments in foreign markets. In addition, investments in certain foreign markets that have historically been considered stable may become more volatile and subject to increased risk due to ongoing developments and changing conditions in such markets. Moreover, the growing interconnectivity of global economies and financial markets has increased the probability that adverse developments and conditions in one country or region will affect the stability of economies and financial markets in other countries or regions. The risks of investing in emerging market countries are greater than the risks associated with investments in foreign developed countries. In addition, the Fund’s investments in foreign issuers may be denominated in foreign currencies and therefore, to the extent unhedged, the value of those investments will fluctuate with U.S. dollar exchange rates. To the extent hedged by the use of foreign currency forward exchange contracts, the precise matching of the foreign currency forward exchange contract amounts and the value of the securities involved will not generally be possible because the future value of such securities in foreign currencies will change as a consequence of market movements in the value of those securities between the date on which the contract is entered into and the date it matures. There is additional risk that such transactions could reduce or preclude the opportunity for gain if the value of the currency moves in the direction opposite to the position

taken and that foreign currency forward exchange contracts create exposure to currencies in which the Fund’s securities are not denominated. The use of foreign currency forward exchange contracts involves the risk of loss from the insolvency or bankruptcy of the counterparty to the contract or the failure of the counterparty to make payments or otherwise comply with the terms of the contract.

•

Liquidity. The Fund’s investments in restricted and illiquid securities may entail greater risk than investments in other types of securities. These securities may be more difficult to sell, particularly in times of market turmoil. Additionally, the market for certain investments deemed liquid at the time of purchase may become illiquid under adverse market or economic conditions. Illiquid securities may be more difficult to value. If the Fund is forced to sell an illiquid security to fund redemptions or for other cash needs, it may be forced to sell the security at a loss or for less than its fair value.

•

Derivatives. A derivative instrument often has risks similar to its underlying asset and may have additional risks, including imperfect correlation between the value of the derivative and the underlying asset, risks of default by the counterparty to certain transactions, magnification of losses incurred due to changes in the market value of the securities, instruments, indices or interest rates to which the derivative instrument relates and risks that the transactions may not be liquid. Certain derivative transactions may give rise to a form of leverage. Leverage magnifies the potential for gain and the risk of loss.

Shares of the Fund are not bank deposits and are not guaranteed or insured by the Federal Deposit Insurance Corporation or any other government agency.

Performance Information

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s Class I shares’ performance from year-to-year and by showing how the Fund’s average annual returns for the past one, five and 10 year periods and since inception compare with those of a broad measure of market performance, as well as an index that represents a group of similar mutual funds, over time. The performance of the other Classes, which is shown in the table below, will differ because the Classes have different ongoing fees. The Fund’s returns in the table include the maximum applicable sales charge for Class A and Class C and assume you sold your shares at the end of each period (unless otherwise noted). The Fund’s past performance, before and after taxes, is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available online at www.morganstanley.com/im or by calling toll-free (800) 548-7786.

Morgan Stanley Institutional Fund, Inc. Prospectus | Fund Summary

International Equity Portfolio (Con’t)

Annual Total Returns—Calendar Years


High Quarter	06/30/09	18.41%
Low Quarter	09/30/11	-17.04%

Average Annual Total Returns

(for the calendar periods ended December 31, 2017)


	Past One Year	Past Five Years	Past Ten Years	Since Inception
Class I (commenced operations on 8/4/1989)
Return Before Taxes	25.17%	6.84%	2.86%	8.60%
Return After Taxes on Distributions¹	24.73%	6.38%	2.32%	7.26%
Return After Taxes on Distributions and Sale of Fund Shares	14.83%	5.38%	2.26%	7.11%
Class A (commenced operations on 1/2/1996)
Return Before Taxes	18.23%	5.34%	2.02%	7.40%
Class L (commenced operations on 6/14/2012)
Return Before Taxes	24.06%	5.94%	N/A	8.28%
Class C (commenced operations on 4/30/2015)
Return Before Taxes	22.78%	N/A	N/A	3.19%
Class IS (commenced operations on 9/13/2013)
Return Before Taxes	25.22%	N/A	N/A	5.20%
MSCI EAFE Index (reflects no deduction for fees, expenses or taxes)²	25.03%	7.90%	1.94%	4.83%⁴
Lipper International Large-Cap Growth Funds Index (reflects no deduction for taxes)³	28.64%	7.45%	2.62%	N/A


(1)	These returns do not reflect any tax consequences from a sale of your shares at the end of each period.
(2)	The MSCI EAFE Index (Europe, Australasia, Far East) is a free float-adjusted market capitalization index that is designed to measure the international equity market performance of developed markets, excluding the United States and Canada. The term “free float” represents the portion of shares outstanding that are deemed to be available for purchase in the public equity markets by investors. The MSCI EAFE Index currently consists of 21 developed market country indices. The performance of the Index is listed in U.S. dollars and assumes reinvestment of net dividends. Net total return indices reinvest dividends after the deduction of withholding taxes, using (for international indices) a tax rate applicable to non-resident institutional investors who do not benefit from double taxation treaties. It is not possible to invest directly in an index.


(3)	The Lipper International Large-Cap Growth Funds Index is an equally-weighted performance index of the largest qualifying funds (based on net assets) in the Lipper International Large-Cap Growth Funds classification. There are currently 30 funds represented in this Index.
(4)	Since Inception reflects the inception date of Class I.

The after-tax returns shown in the table above are calculated using the historical highest individual federal marginal income tax rates during the period shown and do not reflect the impact of state and local taxes. After-tax returns for the Fund’s other Classes will vary from Class I shares’ returns. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and after-tax returns are not relevant to investors who hold their Fund shares through tax deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns may be higher than before-tax returns due to an assumed benefit from capital losses that would have been realized had Fund shares been sold at the end of the relevant periods, as applicable.

Fund Management

Adviser. Morgan Stanley Investment Management Inc.

Sub-Adviser. Morgan Stanley Investment Management Limited.

Portfolio Managers. The Fund is managed by members of the International Equity team. Information about the members jointly and primarily responsible for the day-to-day management of the Fund is shown below:


Name	Title with Sub-Adviser	Date Began Managing Fund
William D. Lock	Managing Director of MSIM Limited	May 1999
Bruno Paulson	Managing Director of MSIM Limited	June 2009
Vladimir A. Demine	Executive Director of MSIM Limited	June 2009
Dirk Hoffmann-Becking	Executive Director of MSIM Limited	January 2015
Nic Sochovsky	Executive Director of MSIM Limited	December 2015
Marcus Watson	Executive Director of MSIM Limited	January 2013
Alex Gabriele	Executive Director of MSIM Limited	September 2017
Richard Perrott	Vice President of MSIM Limited	September 2017

Purchase and Sale of Fund Shares

The Company has suspended offering Class L shares of the Fund for sale to all investors. The Class L shareholders of the Fund do not have the option of purchasing additional Class L shares. However, the existing Class L shareholders may invest in additional Class L shares through reinvestment of dividends and distributions.

The minimum initial investment generally is $5,000,000 for Class I shares and $1,000 for each of Class A and Class C shares of the Fund. To purchase Class IS shares, an investor must meet a minimum initial investment of $10,000,000 or be a defined

Morgan Stanley Institutional Fund, Inc. Prospectus | Fund Summary

International Equity Portfolio (Con’t)

contribution, defined benefit or other employer sponsored employee benefit plan, in each case provided that the plan trades on an omnibus level, whether or not qualified under the Internal Revenue Code of 1986, as amended (the “Code”), and in each case subject to the discretion of the Adviser. The minimum initial investment may be waived for certain investments. For more information, please refer to the section of the Prospectus entitled “Shareholder Information—Minimum Investment Amounts.”

Shares of the Fund may be purchased or sold on any day the New York Stock Exchange (“NYSE”) is open for business directly from the Fund by mail (c/o DST Asset Manager Solutions, Inc., P.O. Box 219804, Kansas City, MO 64121-9804), by telephone (1-800-548-7786) or by contacting an authorized third-party, such as a broker-dealer or other financial intermediary that has entered into a selling agreement with the Fund’s “Distributor,” Morgan Stanley Distribution, Inc. (each a “Financial Intermediary”). In addition, you can sell Fund shares at any time by enrolling in a systematic withdrawal plan. If you sell Class A shares or Class C shares, your net sale proceeds are reduced by the amount of any applicable CDSC. For more information, please refer to the sections of the Prospectus entitled “Shareholder Information—How To Purchase Fund Shares” and “—How To Redeem Fund Shares.”

Tax Information

The Fund intends to make distributions that may be taxed as ordinary income or capital gains, unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or an individual retirement account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a Financial Intermediary (such as a bank), the Adviser and/or the Distributor may pay the Financial Intermediary for the sale of Fund shares and related services. These payments, which may be significant in amount, may create a conflict of interest by influencing the Financial Intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your Financial Intermediary’s web site for more information.

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