U-505 is a German Type IXC submarine built for Germany's Kriegsmarine during World War II. She was captured by the U.S. Navy on 4 June 1944.

In her uniquely unlucky career with the Kriegsmarine, she had the distinction of being the "most heavily damaged U-boat to successfully return to port" in World War II on her fourth patrol, and the only submarine in which a commanding officer took his own life in combat conditions on her tenth patrol, following six botched patrols. She was captured on 4 June 1944 by United States Navy Task Group 22.3 (TG 22.3), one of six U-boats that were captured by Allied forces during World War II. All but one of U-505's crew were rescued by the Navy task group. The submarine was towed to Bermuda in secret and her crew were interned at a US prisoner of war camp, where they were denied access to International Red Cross visits. The Navy classified the capture as top secret and prevented the Germans from discovering it.

In 1954, U-505 was donated to the Museum of Science and Industry in Chicago, Illinois. She is now one of four German World War II U-boats that survive as museum ships, and just one of two Type IXCs still in existence with U-534.