SS Oliver Ellsworth was a Liberty ship built in the United States during World War II.

Oliver Ellsworth was laid down on 31 March 1942, under a Maritime Commission (MARCOM) contract, MCE hull 42, by the Bethlehem-Fairfield Shipyard, Baltimore, Maryland; she was sponsored by Miss Frances T. Cwalina, an Honor Student at Benjamin Franklin Junior High School, Brooklyn, Maryland, and was launched on 22 June 1942.

[5] On 13 September 1942, U-408, sighted the Convoy PQ 18, about 100 mi (160 km) southwest of Spitsbergen, and fired a spread of three torpedoes at 09:52.

After immediately securing the engines, the crew of eight officers, 34 crewmen, and 28 Armed guards quickly abandoned the stricken ship in four lifeboats, due to fear of their cargo of ammunition exploding.

Within an hour the rescue ship Copeland and the A/S trawler HMS St. Kenan, had picked up all the survivors; they were later landed at Archangel.