Document And Entity Information - USD ($)	12 Months Ended
	Jun. 30, 2020	Aug. 20, 2020	Dec. 27, 2019
Document Information [Line Items]
Entity Registrant Name	TWIN DISC INC
Entity Central Index Key	0000100378
Trading Symbol	twin
Current Fiscal Year End Date	--06-30
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding (in shares)		13,552,104
Entity Public Float			$ 107,190,561
Entity Shell Company	false
Document Type	10-K
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Title of 12(b) Security	Common Stock (No Par Value)