The 3d Antiaircraft Artillery Battalion (Composite) (3d AAA Bn (Composite)) was an antiaircraft unit in the United States Marine Corps that served during World War II. The battalion was originally formed in 1943 as the 52d Defense Battalion, one of the first African American units in the Marine Corps. Its original mission was to provide air and coastal defense for advanced naval bases. During the war the battalion served as garrison forces on Roi-Namur, Majuro, and Guam. The battalion returned to Marine Corps Base Camp Lejeune, North Carolina after the war. It was the last of the defense battalions before it was re-designated as the 3d Antiaircraft Artillery Battalion in May 1946. The battalion was decommissioned on May 15, 1947.