Sun Shipbuilding & Drydock Co.

Sun Shipbuilding & Drydock Company (1917–1989) was a major shipbuilding company in Chester, Pennsylvania, about 15 miles south of Philadelphia on the Delaware River. Its primary product was tankers, but the company built many types of ships over its 70-year history. During World War II, it participated in the U.S. Government's Emergency Shipbuilding Program.

The company was developed by Sun Oil Company, and launched its first ship in 1917, just as the United States was entering World War I. By the 1920s, it had become a large shipyard that built tankers for the Standard Oil Company. At the start of World War II, it was among the country's five largest shipyards, with eight slipways. Twenty slipways were added during the war, making Sun Ship the country's biggest shipyard. At its peak, the company employed more than 40,000 workers at four shipyards, including one manned almost entirely by African Americans.

Sun Shipbuilding built 281 T2 tankers during World War II, about 40% of the U.S. wartime total. It also built hospital ships, cargo ships, and escort carriers for the United States Maritime Commission. On 27 September 1941, it contributed one of the 14 Liberty ships launched on Liberty Fleet Day: SS Surprise.