USS O-5 (SS-66) was an O-class submarine. Her keel was laid down on 8 December 1916 by the Fore River Shipbuilding Company of Quincy, Massachusetts. She was launched on 11 November 1917, and commissioned on 8 June 1918 with Lieutenant George A. Trever in command. She sank by collision, with three lives lost, in the Panama Canal Zone 28 October 1923.