Document And Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2023	Nov. 24, 2023	Mar. 24, 2023
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	000-14616
City Area Code	856
Local Phone Number	665-9533
Entity Registrant Name	J&J SNACK FOODS CORP
Entity Incorporation, State or Country Code	NJ
Entity Tax Identification Number	22-1935537
Entity Address, Address Line One	350 Fellowship Road
Entity Address, Postal Zip Code	08054
Entity Address, City or Town	Mt. Laurel
Entity Address, State or Province	NJ
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	JJSF
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 2,198,173,802
Entity Common Stock, Shares Outstanding (in shares)		19,342,344
Auditor Firm ID	248
Auditor Name	GRANT THORNTON LLP
Auditor Location	Philadelphia, Pennsylvania
Entity Central Index Key	0000785956
Current Fiscal Year End Date	--09-24
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false