| 12th Antiaircraft Artillery Battalion | |
|---|---|
 Unofficial 12th Defense Battalion insignia from 1980 Reunion pamphlet | |
| Active | |
| Country |  United States of America |
| Branch |  United States Marine Corps |
| Type | Air Defense/Coastal Defense |
| Size | ~1000 men |
| Part of | I Marine Amphibious Corps[3] |
| Engagements | World War II |
| Commanders | |
| Current commander | N/A |
| Notable commanders | William H. Harrison (USMC) |
The 12th Antiaircraft Artillery Battalion (12th AAA Bn) was a United States Marine Corps antiaircraft unit that served during World War II. Formed in 1942 as the 12th Defense Battalion, its original mission was providing air and coastal defense for advanced naval bases. During the war the battalion defended the Russell Islands and took part in combat operations at Woodlark Island, Cape Gloucester, and Peleliu. The battalion remained on Peleliu for the duration of the war and was finally decommissioned on Guam on 22 September 1945.
- ^ Rottman 2002, pp. 212.
- ^ Rottman 2002, pp. 217.
- ^ Rottman 2004, pp. 28.