The 11th Antiaircraft Artillery Battalion (11th AAA Bn) was a United States Marine Corps antiaircraft unit that served during World War II. Formed in 1942 as the 11th Defense Battalion, its original mission was to provide air and coastal defense for advanced naval bases. During the war the battalion defended took part in combat operations in the Solomon Islands. The battalion's tank platoon also saw extensive action on New Georgia and Arundel Island. The battalion was decommissioned before the end of the war on December 15, 1944.