John Cassidy

John Cassidy may refer to:


 * John Cassidy (artist) (1860–1939), Irish sculptor and painter
 * John Cassidy (baseball) (1855–1891), American baseball player
 * John Cassidy (basketball) (born 1947), Canadian Olympic basketball player
 * John Cassidy (journalist) (born 1963), business journalist and published author
 * John Cassidy (magician) (born 1967), American magician and balloon artist
 * John Cassidy (author), American author and publishing executive
 * John Cassidy (chancellor), Australian businessman and former university chancellor
 * John Cassidy (seismologist) (born 1959), Canadian seismologist
 * John Cassidy (speed skater) (born 1952), Canadian Olympic speed skater
 * Jack Cassidy (1927–1976), American actor
 * John Edward Cassidy (1896–1984), American lawyer; Illinois Attorney General
 * John E. Cassidy Jr (1924—2003), 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 (died 1995), Gaelic football player for Cavan
 * John P. Cassidy (1912–?), Los Angeles City Council member, 1962–1967