Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	497
Document Period End Date	dei_DocumentPeriodEndDate	Feb. 28, 2018
Registrant Name	dei_EntityRegistrantName	GMO TRUST
Central Index Key	dei_EntityCentralIndexKey	0000772129
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Nov. 30, 2018
Document Effective Date	dei_DocumentEffectiveDate	Dec. 03, 2018
Prospectus Date	rr_ProspectusDate	Jun. 30, 2018
GMO Emerging Markets Fund \| Class II
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GMEMX
GMO Emerging Markets Fund \| Class III
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GMOEX
GMO Emerging Markets Fund \| Class IV
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GMEFX
GMO Emerging Markets Fund \| Class V
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GEMVX
GMO Emerging Markets Fund \| Class VI
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GEMMX
GMO Emerging Domestic Opportunities Fund \| Class II
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GEDTX
GMO Emerging Domestic Opportunities Fund \| Class III
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GEDSX
GMO Emerging Domestic Opportunities Fund \| Class IV
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GEDIX
GMO Emerging Domestic Opportunities Fund \| Class V
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GEDOX
GMO Emerging Domestic Opportunities Fund \| Class VI
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GEDFX
GMO Risk Premium Fund \| Class III
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GMRPX
GMO Risk Premium Fund \| Class IV
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GMRVX
GMO Risk Premium Fund \| Class VI
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	GMOKX

If the value is true, then the document is an amendment to previously-filed/accepted document.

No definition available.

Name:	dei_AmendmentFlag
Namespace Prefix:	dei_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

- Definition

The date the document was made available and submitted, in CCYY-MM-DD format. The date of submission, date of acceptance by the recipient, and the document effective date are all potentially different.

+ References

No definition available.

+ Details

Name:	dei_DocumentCreationDate
Namespace Prefix:	dei_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The date when a document, upon receipt and acceptance, becomes officially effective, in CCYY-MM-DD format. Usually it is a system-assigned date time value, but it may be declared by the submitter in some cases.

+ References

No definition available.

+ Details

Name:	dei_DocumentEffectiveDate
Namespace Prefix:	dei_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD.

+ References

No definition available.

+ Details

Name:	dei_DocumentPeriodEndDate
Namespace Prefix:	dei_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word "Other".

+ References

No definition available.

+ Details

Name:	dei_DocumentType
Namespace Prefix:	dei_
Data Type:	dei:submissionTypeItemType
Balance Type:	na
Period Type:	duration

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
-Number 240
-Section 12b
-Subsection 1

+ Details

Name:	dei_EntityCentralIndexKey
Namespace Prefix:	dei_
Data Type:	dei:centralIndexKeyItemType
Balance Type:	na
Period Type:	duration

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
-Number 240
-Section 12b
-Subsection 1

+ Details

Name:	dei_EntityRegistrantName
Namespace Prefix:	dei_
Data Type:	xbrli:normalizedStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Trading symbol of an instrument as listed on an exchange.

+ References

No definition available.

+ Details

Name:	dei_TradingSymbol
Namespace Prefix:	dei_
Data Type:	xbrli:normalizedStringItemType
Balance Type:	na
Period Type:	duration

- Definition

The date of the prospectus.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 1
-Subsection a
-Paragraph 3

+ Details

Name:	rr_ProspectusDate
Namespace Prefix:	rr_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	rr_RiskReturnAbstract
Namespace Prefix:	rr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=gmot_S000004911Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000013268Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000013269Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000013270Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000013271Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000013272Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gmot_S000029579Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000090805Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000090806Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000090807Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000090808Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000090809Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gmot_S000038360Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000118360Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000118361Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rr_ProspectusShareClassAxis=gmot_C000118363Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: