John Cassidy

John Cassidy may refer to:

• John Cassidy (artist), Irish sculptor and painter
• John Cassidy (baseball), American baseball player
• John Cassidy (journalist), business journalist and published author
• John Cassidy (magician), American magician and balloon artist
• John Cassidy (author), American author and publishing executive
• John Cassidy (university chancellor), Australian businessman and former university chancellor
• John Cassidy (seismologist), Canadian seismologist
• Jack Cassidy, American actor