Marine Air Support Squadron 4 (MASS-4) was a reserve United States Marine Corps aviation command and control unit that provided the Direct Air Support Center (DASC) capability from 1962 through the early 1990s. MASS-4 was headquartered at Naval Air Station Los Alamitos, California, and was part of Marine Air Control Group 48 (MACG-48) and the 4th Marine Aircraft Wing (4th MAW).