Donald Bradley Duncan (1896–1975) was an admiral in the United States Navy, who played an important role in aircraft-carrier operations during World War II.

Duncan graduated from the United States Naval Academy in 1917, and was assigned to the USS Oklahoma (BB-37).

In July 1935, Duncan assumed command of Scouting Squadron 3B (VS-3B) assigned to USS Lexington (CV-2).

In 1941, he was the first commander of the USS Long Island, the Navy's first escort aircraft carrier.

He served as Deputy Chief of Naval Operations (Air) from March 6, 1947, to January 20, 1948.