Cassidy may refer to:

• Cassidy (given name)
• Cassidy (surname)

• Cassidy (musician) (born 1979), lead singer of Antigone Rising
• Cassidy (rapper) (born 1982), American rapper
• DJ Cassidy (born 1981), New York DJ
• Orange Cassidy, a stage name of professional wrestler James Cipperly (born 1984)

• Cole Cassidy, a fictional character in the Blizzard Entertainment's 2016 video game Overwatch
• Cassidy (DC Comics), a vampire from the graphic novel Preacher
• Cassidy, role played by actor Sam Slovick in the television show Fame
• Charles Parnell Cassidy, a fictional premier of New South Wales in the novel and TV film Cassidy
• Cassidy, a fictional character from Five Nights at Freddy's
• Hopalong Cassidy, fictional cowboy

• Casady & Greene, software company (1984–2003) that produced software for the Macintosh

• Cassidy, British Columbia, a settlement and airport in Canada
• Maggie Cassidy, a 1959 novel by Jack Kerouac
• Cassidy's Ltd., a defunct Canadian company
• "Cassidy" (song), a 1972 song by the Grateful Dead
• Cassidy (miniseries), a 1989 Australian miniseries based on a 1986 novel by Morris West

• Cassady (disambiguation)