Document And Entity Information - USD ($)	12 Months Ended
	Jun. 30, 2021	Aug. 20, 2021	Dec. 25, 2020
Document Information [Line Items]
Entity Central Index Key	0000100378
Entity Registrant Name	TWIN DISC INC
Amendment Flag	false
Current Fiscal Year End Date	--06-30
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2021
Document Type	10-K
Document Annual Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	1-7635
Entity Incorporation, State or Country Code	WI
Entity Tax Identification Number	39-0667110
Entity Address, Address Line One	1328 Racine Street
Entity Address, City or Town	Racine
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	53403
City Area Code	262
Local Phone Number	638‑4000
Title of 12(b) Security	Common Stock (No Par Value)
Trading Symbol	TWIN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 77,500,872
Entity Common Stock, Shares Outstanding		13,654,965
ICFR Auditor Attestation Flag	true