Document And Entity Information - shares	9 Months Ended
	Jun. 29, 2018	Aug. 01, 2018
Document Information [Line Items]
Entity Registrant Name	LEARNING TREE INTERNATIONAL, INC.
Entity Central Index Key	0001002037
Trading Symbol	ltre
Current Fiscal Year End Date	--09-28
Entity Filer Category	Smaller Reporting Company
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		13,224,349
Document Type	10-Q
Document Period End Date	Jun. 29, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Amendment Flag	false