Shaun Paul Cassidy (born September 27, 1958 in Los Angeles, California) is an American singer and actor.

The eldest of Broadway entertainer Jack Cassidy's and actress Shirley Jones's three sons, Cassidy was inspired by the success of his half-brother David Cassidy of the Partridge Family. He went to the same High School as Angelina Jolie, Nicolas Cage, David Schwimmer and Lenny Kravitz.

He released several successful singles in the late 1970s with his first single, a cover version of The Crystals "Da Do Ron Ron", hit #1 in the United States in 1977, and, like David, became a major teen idol. He achieved two further top ten singles with cover versions of Eric Carmen 's "That's Rock 'N' Roll" and "Hey Deanie" the same year.

Cassidy starred opposite Parker Stevenson in the popular Hardy Boys television series which ran for several seasons on ABC-TV starting in 1978. Cassidy made his Broadway debut in 1993 in a production of Blood Brothers.

Cassidy has ventured into writing and producing. Among his credits are the hit CBS shows Cold Case and The Agency.

He has 2 children by his first wife, model Ann Pennington, and 1 child by his second wife, actress Susan Diol. On August 28, 2004, he married his third wife, producer Tracey Turner.