Also dismissed were assistant coaches Greg Carvel and Brad Lauer, Ottawa General Manager Bryan Murray said.
Clouston, 41, failed to take the team into the playoffs for the second time in three years. They finished last in the Northeast Division with a 32-40-10 record after finishing second last season and fourth the year before.
Clouston compiled a 95-83-20 record as head coach after being promoted from the Senators' American Hockey League affiliate in Binghamton, N.Y., on Feb. 2, 2009.
Swim Week Miami Beach 2014 [PHOTOS]