497

Morgan, Lewis & Bockius LLP

101 Park Avenue

New York, NY 10178-0060

November 21, 2018

VIA EDGAR

Securities and Exchange Commission

Division of Investment Management

100 F Street, NE

Washington, DC 20549

Re: Legg Mason Global Asset Management Trust (the “Registrant”)

(Filing relates to RARE Global Infrastructure Value Fund (the “Fund”))

(File Nos. 333-162441 and 811-22338)

Ladies and Gentlemen:

On behalf of the Registrant and pursuant to Rule 497(e) under the Securities Act of 1933, as amended, attached for filing are exhibits containing in interactive data format the risk/return summary information that appears in a supplement dated November 6, 2018 to the summary prospectus and prospectus for the Fund.

Please call the undersigned at (212) 309-6353 with any comments or questions relating to the filing.

Sincerely,

/s/ Elizabeth L. Belanger

Elizabeth L. Belanger

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	497
Document Period End Date	dei_DocumentPeriodEndDate	Sep. 30, 2017
Registrant Name	dei_EntityRegistrantName	Legg Mason Global Asset Management Trust
Central Index Key	dei_EntityCentralIndexKey	0001474103
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Nov. 06, 2018
Document Effective Date	dei_DocumentEffectiveDate	Nov. 06, 2018
Prospectus Date	rr_ProspectusDate	Feb. 01, 2018
Entity Inv Company Type	dei_EntityInvCompanyType	N-1A

XML

Feb. 01, 2018

LEGG MASON GLOBAL ASSET MANAGEMENT TRUST

SUPPLEMENT DATED NOVEMBER 6, 2018

TO THE SUMMARY PROSPECTUS, PROSPECTUS

AND STATEMENT OF ADDITIONAL INFORMATION

EACH DATED FEBRUARY 1, 2018, OF

RARE GLOBAL INFRASTRUCTURE VALUE FUND (THE “FUND”)

Effective November 2, 2018, the Fund's management fee was reduced from a fee schedule that started at 0.90% of the Fund's average daily net assets and decreased to 0.80% as assets increased, to a flat rate of 0.80% of the Fund's average daily net assets.

In addition, effective November 2, 2018, the Fund replaced its current broad-based benchmark index, the MSCI World Core Infrastructure Index, with the S&P Global Infrastructure Index (the "S&P Index"). Legg Mason Partners Fund Advisor, LLC ("LMPFA") and the Fund's subadviser believe the S&P Index is a more appropriate benchmark for the Fund.

As a result, the following changes are made to the Fund's Summary Prospectus, Prospectus and Statement of Additional Information:

The following replaces the fee table and footnotes and expense example in the section of the Fund's Summary Prospectus and Prospectus entitled "Fees and expenses of the fund":

Shareholder fees
(fees paid directly from your investment)
	Class A	Class A2	Class C	Class FI	Class R	Class I	Class IS
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.751,2	5.75	None	None	None	None	None
Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)3	None4	None4	1.00	None	None	None	None
Small account fee5	$15	$15	$15	None	None	None	None
Annual fund operating expenses (%)
(expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class A2	Class C	Class FI	Class R	Class I	Class IS
Management fees6	0.80	0.80	0.80	0.80	0.80	0.80	0.80
Distribution and/or service (12b-1) fees	0.25	0.25	1.00	0.25	0.50	None	None
Other expenses	0.737	0.938	0.738	0.838	0.838	0.707	0.637
Total annual fund operating expenses	1.78	1.98	2.53	1.88	2.13	1.50	1.43
Fees waived and/or expenses reimbursed9	(0.43)	(0.43)	(0.43)	(0.53)	(0.53)	(0.50)	(0.53)
Total annual fund operating expenses after waiving fees and/or reimbursing expenses	1.35	1.55	2.10	1.35	1.60	1.00	0.90

¹ The sales charge is waived for shareholders purchasing Class A shares through accounts where LMIS is the broker-dealer of record (“LMIS Accounts”).

² Shareholders purchasing Class A shares through certain Service Agents or in certain types of accounts may be eligible for a waiver of the sales charge. For additional information, see “Sales charges” in the Prospectus.

³ Maximum deferred sales charge (load) may be reduced over time.

⁴ You may buy Class A or Class A2 shares in amounts of $1,000,000 or more at net asset value (without an initial sales charge), but if you redeem those shares within 18 months of their purchase, you will pay a contingent deferred sales charge of 1.00%.

⁵ If the value of your account is below $1,000 ($250 for retirement plans that are not employer-sponsored), the fund may charge you a fee of $3.75 per account that is determined and assessed quarterly by the fund or your Service Agent (with an annual maximum of $15.00 per account). Please contact your Service Agent or the fund for more information.

⁶ The Fund's management fees have been restated to reflect current fees.

⁷ "Other expenses" for Class A, I and IS shares have been restated to reflect expenses as of March 31, 2018.

⁸ "Other expenses" for Class A2, C, FI and R shares are estimated for the current fiscal year. Actual expenses may differ from estimates.

⁹ The manager has agreed to waive fees and/or reimburse operating expenses (other than interest, brokerage commissions, taxes, extraordinary expenses and acquired fund fees and expenses) so that the ratio of total annual fund operating expenses will not exceed 1.35% for Class A shares, 1.55% for Class A2 shares, 2.10% for Class C shares, 1.35% for Class FI shares, 1.60% for Class R shares, 1.00% for Class I shares and 0.90% for Class IS shares, subject to recapture as described below. In addition, the ratio of total annual fund operating expenses for Class IS shares will not exceed the ratio of total annual fund operating expenses for Class I shares, subject to recapture as described below. These arrangements cannot be terminated prior to December 31, 2019 without the Board of Trustees' consent. The manager is permitted to recapture amounts waived and/or reimbursed to a class within three years after the fiscal year in which the manager earned the fee or incurred the expense if the class' total annual fund operating expenses have fallen to a level below the limits described above. In no case will the manager recapture any amount that would result, on any particular business day of the fund, in the class' total annual fund operating expenses exceeding the applicable limits described above or any other lower limit then in effect.

Example

This example 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:

• You invest $10,000 in the fund for the time periods indicated

• Your investment has a 5% return each year and the fund’s operating expenses remain the same

• You reinvest all distributions and dividends without a sales charge

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Number of years you own your shares ($)
	1 year	3 years	5 years	10 years
Class A (with or without redemption at end of period)	705	1,064	1,446	2,517
Class A2 (with or without redemption at end of period)	724	1,122	1,544	2,716
Class C (with redemption at end of period)	313	747	1,308	2,835
Class C (without redemption at end of period)	213	747	1,308	2,835
Class FI (with or without redemption at end of period)	137	539	966	2,157
Class R (with or without redemption at end of period)	163	616	1,095	2,419
Class I (with or without redemption at end of period)	102	425	771	1,748
Class IS (with or without redemption at end of period)	92	401	732	1,669

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

Legg Mason Global Asset Management Trust

Prospectus Date

rr_ProspectusDate

Feb. 01, 2018

Supplement to Prospectus [Text Block]

rr_SupplementToProspectusTextBlock

LEGG MASON GLOBAL ASSET MANAGEMENT TRUST

SUPPLEMENT DATED NOVEMBER 6, 2018

TO THE SUMMARY PROSPECTUS, PROSPECTUS

AND STATEMENT OF ADDITIONAL INFORMATION

EACH DATED FEBRUARY 1, 2018, OF

RARE GLOBAL INFRASTRUCTURE VALUE FUND (THE “FUND”)

Effective November 2, 2018, the Fund's management fee was reduced from a fee schedule that started at 0.90% of the Fund's average daily net assets and decreased to 0.80% as assets increased, to a flat rate of 0.80% of the Fund's average daily net assets.

In addition, effective November 2, 2018, the Fund replaced its current broad-based benchmark index, the MSCI World Core Infrastructure Index, with the S&P Global Infrastructure Index (the "S&P Index"). Legg Mason Partners Fund Advisor, LLC ("LMPFA") and the Fund's subadviser believe the S&P Index is a more appropriate benchmark for the Fund.

As a result, the following changes are made to the Fund's Summary Prospectus, Prospectus and Statement of Additional Information:

The following replaces the fee table and footnotes and expense example in the section of the Fund's Summary Prospectus and Prospectus entitled "Fees and expenses of the fund":

Shareholder fees
(fees paid directly from your investment)
	Class A	Class A2	Class C	Class FI	Class R	Class I	Class IS
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.751,2	5.75	None	None	None	None	None
Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)3	None4	None4	1.00	None	None	None	None
Small account fee5	$15	$15	$15	None	None	None	None
Annual fund operating expenses (%)
(expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class A2	Class C	Class FI	Class R	Class I	Class IS
Management fees6	0.80	0.80	0.80	0.80	0.80	0.80	0.80
Distribution and/or service (12b-1) fees	0.25	0.25	1.00	0.25	0.50	None	None
Other expenses	0.737	0.938	0.738	0.838	0.838	0.707	0.637
Total annual fund operating expenses	1.78	1.98	2.53	1.88	2.13	1.50	1.43
Fees waived and/or expenses reimbursed9	(0.43)	(0.43)	(0.43)	(0.53)	(0.53)	(0.50)	(0.53)
Total annual fund operating expenses after waiving fees and/or reimbursing expenses	1.35	1.55	2.10	1.35	1.60	1.00	0.90

¹ The sales charge is waived for shareholders purchasing Class A shares through accounts where LMIS is the broker-dealer of record (“LMIS Accounts”).

² Shareholders purchasing Class A shares through certain Service Agents or in certain types of accounts may be eligible for a waiver of the sales charge. For additional information, see “Sales charges” in the Prospectus.

³ Maximum deferred sales charge (load) may be reduced over time.

⁴ You may buy Class A or Class A2 shares in amounts of $1,000,000 or more at net asset value (without an initial sales charge), but if you redeem those shares within 18 months of their purchase, you will pay a contingent deferred sales charge of 1.00%.

⁵ If the value of your account is below $1,000 ($250 for retirement plans that are not employer-sponsored), the fund may charge you a fee of $3.75 per account that is determined and assessed quarterly by the fund or your Service Agent (with an annual maximum of $15.00 per account). Please contact your Service Agent or the fund for more information.

⁶ The Fund's management fees have been restated to reflect current fees.

⁷ "Other expenses" for Class A, I and IS shares have been restated to reflect expenses as of March 31, 2018.

⁸ "Other expenses" for Class A2, C, FI and R shares are estimated for the current fiscal year. Actual expenses may differ from estimates.

⁹ The manager has agreed to waive fees and/or reimburse operating expenses (other than interest, brokerage commissions, taxes, extraordinary expenses and acquired fund fees and expenses) so that the ratio of total annual fund operating expenses will not exceed 1.35% for Class A shares, 1.55% for Class A2 shares, 2.10% for Class C shares, 1.35% for Class FI shares, 1.60% for Class R shares, 1.00% for Class I shares and 0.90% for Class IS shares, subject to recapture as described below. In addition, the ratio of total annual fund operating expenses for Class IS shares will not exceed the ratio of total annual fund operating expenses for Class I shares, subject to recapture as described below. These arrangements cannot be terminated prior to December 31, 2019 without the Board of Trustees' consent. The manager is permitted to recapture amounts waived and/or reimbursed to a class within three years after the fiscal year in which the manager earned the fee or incurred the expense if the class' total annual fund operating expenses have fallen to a level below the limits described above. In no case will the manager recapture any amount that would result, on any particular business day of the fund, in the class' total annual fund operating expenses exceeding the applicable limits described above or any other lower limit then in effect.

Example

This example 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:

• You invest $10,000 in the fund for the time periods indicated

• Your investment has a 5% return each year and the fund’s operating expenses remain the same

• You reinvest all distributions and dividends without a sales charge

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Number of years you own your shares ($)
	1 year	3 years	5 years	10 years
Class A (with or without redemption at end of period)	705	1,064	1,446	2,517
Class A2 (with or without redemption at end of period)	724	1,122	1,544	2,716
Class C (with redemption at end of period)	313	747	1,308	2,835
Class C (without redemption at end of period)	213	747	1,308	2,835
Class FI (with or without redemption at end of period)	137	539	966	2,157
Class R (with or without redemption at end of period)	163	616	1,095	2,419
Class I (with or without redemption at end of period)	102	425	771	1,748
Class IS (with or without redemption at end of period)	92	401	732	1,669

RARE Global Infrastructure Value Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement to Prospectus [Text Block]

rr_SupplementToProspectusTextBlock

LEGG MASON GLOBAL ASSET MANAGEMENT TRUST

SUPPLEMENT DATED NOVEMBER 6, 2018

TO THE SUMMARY PROSPECTUS, PROSPECTUS

AND STATEMENT OF ADDITIONAL INFORMATION

EACH DATED FEBRUARY 1, 2018, OF

RARE GLOBAL INFRASTRUCTURE VALUE FUND (THE “FUND”)

Effective November 2, 2018, the Fund's management fee was reduced from a fee schedule that started at 0.90% of the Fund's average daily net assets and decreased to 0.80% as assets increased, to a flat rate of 0.80% of the Fund's average daily net assets.

In addition, effective November 2, 2018, the Fund replaced its current broad-based benchmark index, the MSCI World Core Infrastructure Index, with the S&P Global Infrastructure Index (the "S&P Index"). Legg Mason Partners Fund Advisor, LLC ("LMPFA") and the Fund's subadviser believe the S&P Index is a more appropriate benchmark for the Fund.

As a result, the following changes are made to the Fund's Summary Prospectus, Prospectus and Statement of Additional Information:

The following replaces the fee table and footnotes and expense example in the section of the Fund's Summary Prospectus and Prospectus entitled "Fees and expenses of the fund":

Shareholder fees
(fees paid directly from your investment)
	Class A	Class A2	Class C	Class FI	Class R	Class I	Class IS
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.751,2	5.75	None	None	None	None	None
Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)3	None4	None4	1.00	None	None	None	None
Small account fee5	$15	$15	$15	None	None	None	None
Annual fund operating expenses (%)
(expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class A2	Class C	Class FI	Class R	Class I	Class IS
Management fees6	0.80	0.80	0.80	0.80	0.80	0.80	0.80
Distribution and/or service (12b-1) fees	0.25	0.25	1.00	0.25	0.50	None	None
Other expenses	0.737	0.938	0.738	0.838	0.838	0.707	0.637
Total annual fund operating expenses	1.78	1.98	2.53	1.88	2.13	1.50	1.43
Fees waived and/or expenses reimbursed9	(0.43)	(0.43)	(0.43)	(0.53)	(0.53)	(0.50)	(0.53)
Total annual fund operating expenses after waiving fees and/or reimbursing expenses	1.35	1.55	2.10	1.35	1.60	1.00	0.90

¹ The sales charge is waived for shareholders purchasing Class A shares through accounts where LMIS is the broker-dealer of record (“LMIS Accounts”).

² Shareholders purchasing Class A shares through certain Service Agents or in certain types of accounts may be eligible for a waiver of the sales charge. For additional information, see “Sales charges” in the Prospectus.

³ Maximum deferred sales charge (load) may be reduced over time.

⁴ You may buy Class A or Class A2 shares in amounts of $1,000,000 or more at net asset value (without an initial sales charge), but if you redeem those shares within 18 months of their purchase, you will pay a contingent deferred sales charge of 1.00%.

⁵ If the value of your account is below $1,000 ($250 for retirement plans that are not employer-sponsored), the fund may charge you a fee of $3.75 per account that is determined and assessed quarterly by the fund or your Service Agent (with an annual maximum of $15.00 per account). Please contact your Service Agent or the fund for more information.

⁶ The Fund's management fees have been restated to reflect current fees.

⁷ "Other expenses" for Class A, I and IS shares have been restated to reflect expenses as of March 31, 2018.

⁸ "Other expenses" for Class A2, C, FI and R shares are estimated for the current fiscal year. Actual expenses may differ from estimates.

⁹ The manager has agreed to waive fees and/or reimburse operating expenses (other than interest, brokerage commissions, taxes, extraordinary expenses and acquired fund fees and expenses) so that the ratio of total annual fund operating expenses will not exceed 1.35% for Class A shares, 1.55% for Class A2 shares, 2.10% for Class C shares, 1.35% for Class FI shares, 1.60% for Class R shares, 1.00% for Class I shares and 0.90% for Class IS shares, subject to recapture as described below. In addition, the ratio of total annual fund operating expenses for Class IS shares will not exceed the ratio of total annual fund operating expenses for Class I shares, subject to recapture as described below. These arrangements cannot be terminated prior to December 31, 2019 without the Board of Trustees' consent. The manager is permitted to recapture amounts waived and/or reimbursed to a class within three years after the fiscal year in which the manager earned the fee or incurred the expense if the class' total annual fund operating expenses have fallen to a level below the limits described above. In no case will the manager recapture any amount that would result, on any particular business day of the fund, in the class' total annual fund operating expenses exceeding the applicable limits described above or any other lower limit then in effect.

Example

This example 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:

• You invest $10,000 in the fund for the time periods indicated

• Your investment has a 5% return each year and the fund’s operating expenses remain the same

• You reinvest all distributions and dividends without a sales charge

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Number of years you own your shares ($)
	1 year	3 years	5 years	10 years
Class A (with or without redemption at end of period)	705	1,064	1,446	2,517
Class A2 (with or without redemption at end of period)	724	1,122	1,544	2,716
Class C (with redemption at end of period)	313	747	1,308	2,835
Class C (without redemption at end of period)	213	747	1,308	2,835
Class FI (with or without redemption at end of period)	137	539	966	2,157
Class R (with or without redemption at end of period)	163	616	1,095	2,419
Class I (with or without redemption at end of period)	102	425	771	1,748
Class IS (with or without redemption at end of period)	92	401	732	1,669

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

<b>Shareholder fees</b><br/>(fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

<b>Annual fund operating expenses (%)</b><br/>(expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

December 31, 2019

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

You may buy Class A or Class A2 shares in amounts of $1,000,000 or more at net asset value (without an initial sales charge), but if you redeem those shares within 18 months of their purchase, you will pay a contingent deferred sales charge of 1.00%.

Other Expenses, New Fund, Based on Estimates [Text]

rr_OtherExpensesNewFundBasedOnEstimates

“Other expenses” for Class A2, C, FI and R shares are estimated for the current fiscal year. Actual expenses may differ from estimates.

Expenses Restated to Reflect Current [Text]

rr_ExpensesRestatedToReflectCurrent

The Fund's management fees have been restated to reflect current fees.<br/><br/>“Other expenses” for Class A, I and IS shares have been restated to reflect expenses as of March 31, 2018.

Expense Example [Heading]

rr_ExpenseExampleHeading

<b>Example </b>

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example 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:

• You invest $10,000 in the fund for the time periods indicated

• Your investment has a 5% return each year and the fund’s operating expenses remain the same

• You reinvest all distributions and dividends without a sales charge

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

<b>Number of years you own your shares ($)</b>

Expense Example, No Redemption, By Year, Caption [Text]

rr_ExpenseExampleNoRedemptionByYearCaption

<b>Number of years you own your shares ($)</b>

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

In addition, effective November 2, 2018, the Fund replaced its current broad-based benchmark index, the MSCI World Core Infrastructure Index, with the S&P Global Infrastructure Index (the "S&P Index"). Legg Mason Partners Fund Advisor, LLC ("LMPFA") and the Fund's subadviser believe the S&P Index is a more appropriate benchmark for the Fund.

RARE Global Infrastructure Value Fund | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

^[1],[2]

Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)

rr_MaximumDeferredSalesChargeOverOther

none

^[3],[4]

Small account fee ($)

rr_MaximumAccountFee

$ 15

^[5]

Management fees

rr_ManagementFeesOverAssets

0.80%

^[6]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.73%

^[7]

Total annual fund operating expenses

rr_ExpensesOverAssets

1.78%

Fees waived and/or expenses reimbursed

rr_FeeWaiverOrReimbursementOverAssets

(0.43%)

^[8]

Total annual fund operating expenses after waiving fees and/or reimbursing expenses

rr_NetExpensesOverAssets

1.35%

1 year

rr_ExpenseExampleYear01

$ 705

3 years

rr_ExpenseExampleYear03

1,064

5 years

rr_ExpenseExampleYear05

1,446

10 years

rr_ExpenseExampleYear10

2,517

1 year

rr_ExpenseExampleNoRedemptionYear01

705

3 years

rr_ExpenseExampleNoRedemptionYear03

1,064

5 years

rr_ExpenseExampleNoRedemptionYear05

1,446

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,517

RARE Global Infrastructure Value Fund | Class A2

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)

rr_MaximumDeferredSalesChargeOverOther

none

^[3],[4]

Small account fee ($)

rr_MaximumAccountFee

$ 15

^[5]

Management fees

rr_ManagementFeesOverAssets

0.80%

^[6]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.93%

^[9]

Total annual fund operating expenses

rr_ExpensesOverAssets

1.98%

Fees waived and/or expenses reimbursed

rr_FeeWaiverOrReimbursementOverAssets

(0.43%)

^[8]

Total annual fund operating expenses after waiving fees and/or reimbursing expenses

rr_NetExpensesOverAssets

1.55%

1 year

rr_ExpenseExampleYear01

$ 724

3 years

rr_ExpenseExampleYear03

1,122

5 years

rr_ExpenseExampleYear05

1,544

10 years

rr_ExpenseExampleYear10

2,716

1 year

rr_ExpenseExampleNoRedemptionYear01

724

3 years

rr_ExpenseExampleNoRedemptionYear03

1,122

5 years

rr_ExpenseExampleNoRedemptionYear05

1,544

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,716

RARE Global Infrastructure Value Fund | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[3]

Small account fee ($)

rr_MaximumAccountFee

$ 15

^[5]

Management fees

rr_ManagementFeesOverAssets

0.80%

^[6]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.73%

^[9]

Total annual fund operating expenses

rr_ExpensesOverAssets

2.53%

Fees waived and/or expenses reimbursed

rr_FeeWaiverOrReimbursementOverAssets

(0.43%)

^[8]

Total annual fund operating expenses after waiving fees and/or reimbursing expenses

rr_NetExpensesOverAssets

2.10%

1 year

rr_ExpenseExampleYear01

$ 313

3 years

rr_ExpenseExampleYear03

747

5 years

rr_ExpenseExampleYear05

1,308

10 years

rr_ExpenseExampleYear10

2,835

1 year

rr_ExpenseExampleNoRedemptionYear01

213

3 years

rr_ExpenseExampleNoRedemptionYear03

747

5 years

rr_ExpenseExampleNoRedemptionYear05

1,308

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,835

RARE Global Infrastructure Value Fund | Class FI

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)

rr_MaximumDeferredSalesChargeOverOther

none

^[3]

Small account fee ($)

rr_MaximumAccountFee

none

^[5]

Management fees

rr_ManagementFeesOverAssets

0.80%

^[6]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.83%

^[9]

Total annual fund operating expenses

rr_ExpensesOverAssets

1.88%

Fees waived and/or expenses reimbursed

rr_FeeWaiverOrReimbursementOverAssets

(0.53%)

^[8]

Total annual fund operating expenses after waiving fees and/or reimbursing expenses

rr_NetExpensesOverAssets

1.35%

1 year

rr_ExpenseExampleYear01

$ 137

3 years

rr_ExpenseExampleYear03

539

5 years

rr_ExpenseExampleYear05

966

10 years

rr_ExpenseExampleYear10

2,157

1 year

rr_ExpenseExampleNoRedemptionYear01

137

3 years

rr_ExpenseExampleNoRedemptionYear03

539

5 years

rr_ExpenseExampleNoRedemptionYear05

966

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,157

RARE Global Infrastructure Value Fund | Class R

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)

rr_MaximumDeferredSalesChargeOverOther

none

^[3]

Small account fee ($)

rr_MaximumAccountFee

none

^[5]

Management fees

rr_ManagementFeesOverAssets

0.80%

^[6]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.50%

Other expenses

rr_OtherExpensesOverAssets

0.83%

^[9]

Total annual fund operating expenses

rr_ExpensesOverAssets

2.13%

Fees waived and/or expenses reimbursed

rr_FeeWaiverOrReimbursementOverAssets

(0.53%)

^[8]

Total annual fund operating expenses after waiving fees and/or reimbursing expenses

rr_NetExpensesOverAssets

1.60%

1 year

rr_ExpenseExampleYear01

$ 163

3 years

rr_ExpenseExampleYear03

616

5 years

rr_ExpenseExampleYear05

1,095

10 years

rr_ExpenseExampleYear10

2,419

1 year

rr_ExpenseExampleNoRedemptionYear01

163

3 years

rr_ExpenseExampleNoRedemptionYear03

616

5 years

rr_ExpenseExampleNoRedemptionYear05

1,095

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,419

RARE Global Infrastructure Value Fund | Class I

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)

rr_MaximumDeferredSalesChargeOverOther

none

^[3]

Small account fee ($)

rr_MaximumAccountFee

none

^[5]

Management fees

rr_ManagementFeesOverAssets

0.80%

^[6]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.70%

^[7]

Total annual fund operating expenses

rr_ExpensesOverAssets

1.50%

Fees waived and/or expenses reimbursed

rr_FeeWaiverOrReimbursementOverAssets

(0.50%)

^[8]

Total annual fund operating expenses after waiving fees and/or reimbursing expenses

rr_NetExpensesOverAssets

1.00%

1 year

rr_ExpenseExampleYear01

$ 102

3 years

rr_ExpenseExampleYear03

425

5 years

rr_ExpenseExampleYear05

771

10 years

rr_ExpenseExampleYear10

1,748

1 year

rr_ExpenseExampleNoRedemptionYear01

102

3 years

rr_ExpenseExampleNoRedemptionYear03

425

5 years

rr_ExpenseExampleNoRedemptionYear05

771

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,748

RARE Global Infrastructure Value Fund | Class IS

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)

rr_MaximumDeferredSalesChargeOverOther

none

^[3]

Small account fee ($)

rr_MaximumAccountFee

none

^[5]

Management fees

rr_ManagementFeesOverAssets

0.80%

^[6]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.63%

^[7]

Total annual fund operating expenses

rr_ExpensesOverAssets

1.43%

Fees waived and/or expenses reimbursed

rr_FeeWaiverOrReimbursementOverAssets

(0.53%)

^[8]

Total annual fund operating expenses after waiving fees and/or reimbursing expenses

rr_NetExpensesOverAssets

0.90%

1 year

rr_ExpenseExampleYear01

$ 92

3 years

rr_ExpenseExampleYear03

401

5 years

rr_ExpenseExampleYear05

732

10 years

rr_ExpenseExampleYear10

1,669

1 year

rr_ExpenseExampleNoRedemptionYear01

92

3 years

rr_ExpenseExampleNoRedemptionYear03

401

5 years

rr_ExpenseExampleNoRedemptionYear05

732

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,669

[1] Shareholders purchasing Class A shares through certain Service Agents or in certain types of accounts may be eligible for a waiver of the sales charge. For additional information, see “Sales charges” in the Prospectus.

[2] The sales charge is waived for shareholders purchasing Class A shares through accounts where LMIS is the broker-dealer of record (“LMIS Accounts”).

[3] Maximum deferred sales charge (load) may be reduced over time.

[4] You may buy Class A or Class A2 shares in amounts of $1,000,000 or more at net asset value (without an initial sales charge), but if you redeem those shares within 18 months of their purchase, you will pay a contingent deferred sales charge of 1.00%.

[5] If the value of your account is below $1,000 ($250 for retirement plans that are not employer-sponsored), the fund may charge you a fee of $3.75 per account that is determined and assessed quarterly by the fund or your Service Agent (with an annual maximum of $15.00 per account). Please contact your Service Agent or the fund for more information.

[6] The Fund’s management fees have been restated to reflect current fees.

[7] "Other expenses" for Class A, I and IS shares have been restated to reflect expenses as of March 31, 2018.

[8] The manager has agreed to waive fees and/or reimburse operating expenses (other than interest, brokerage commissions, taxes, extraordinary expenses and acquired fund fees and expenses) so that the ratio of total annual fund operating expenses will not exceed 1.35% for Class A shares, 1.55% for Class A2 shares, 2.10% for Class C shares, 1.35% for Class FI shares, 1.60% for Class R shares, 1.00% for Class I shares and 0.90% for Class IS shares, subject to recapture as described below. In addition, the ratio of total annual fund operating expenses for Class IS shares will not exceed the ratio of total annual fund operating expenses for Class I shares, subject to recapture as described below. These arrangements cannot be terminated prior to December 31, 2019 without the Board of Trustees’ consent. The manager is permitted to recapture amounts waived and/or reimbursed to a class within three years after the fiscal year in which the manager earned the fee or incurred the expense if the class’ total annual fund operating expenses have fallen to a level below the limits described above. In no case will the manager recapture any amount that would result, on any particular business day of the fund, in the class’ total annual fund operating expenses exceeding the applicable limits described above or any other lower limit then in effect.

[9] “Other expenses” for Class A2, C, FI and R shares are estimated for the current fiscal year. Actual expenses may differ from estimates.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	Legg Mason Global Asset Management Trust
Prospectus Date	rr_ProspectusDate	Feb. 01, 2018
Document Creation Date	dei_DocumentCreationDate	Nov. 06, 2018