John Cassidy
John Cassidy may refer to:
- John Cassidy , Irish sculptor and painter
- John Cassidy , American baseball player
- John Cassidy , Canadian Olympic basketball player
- John Cassidy , business journalist and published author
- John Cassidy , American magician and balloon artist
- John Cassidy , American author and publishing executive
- John Cassidy , Australian businessman and former university chancellor
- John Cassidy , Canadian seismologist
- John Cassidy , Canadian Olympic speed skater
- Jack Cassidy, American actor
- John Edward Cassidy, American lawyer; Illinois Attorney General
- John E. Cassidy Jr, member of the Illinois House of Representatives.
- John F. Cassidy, Vice Chairman of the board and former Chief Executive Officer of Cincinnati Bell Inc.
- John Joe Cassidy, Gaelic football player for Cavan
- John P. Cassidy, Los Angeles City Council member, 1962–1967