Rocketdyne was an American rocket engine design and production company headquartered in Canoga Park, in the western San Fernando Valley of suburban Los Angeles, in southern California.

The Rocketdyne Division was founded by North American Aviation (NAA) in 1955, and was later part of Rockwell International (1967-1996) and Boeing (1996-2005). In 2005, the Rocketdyne Division was sold to United Technologies Corporation, becoming Pratt & Whitney Rocketdyne as part of Pratt & Whitney. In 2013, Pratt & Whitney Rocketdyne was sold to GenCorp, which merged it with Aerojet to form Aerojet Rocketdyne.