Marine Aviation and Training Support Group 23 (MATSG-23) is a United States Marine Corps aviation training group that was originally established during World War II as Marine Aircraft Group 23 (MAG-23). Squadrons from MAG-23, augmented by Navy and Army flying units formed the Cactus Air Force during the Battle of Guadalcanal. The group was deactivated at the end of the war and was not reactivated until January 15, 1982 when Marine Aviation and Training Support Group NAS Lemoore was renamed MATSG-23.