The 4735th Air Defense Group is a discontinued United States Air Force organization. It was assigned to the Boston Air Defense Sector throughout its existence at Otis Air Force Base, Massachusetts, where it was last active in 1959. The group was formed to provide a single command and support organization for the two fighter interceptor squadrons of Air Defense Command (ADC) at Otis, when the 33d Fighter Wing inactivated and the 551st Airborne Early Warning and Control Wing became the host at Otis. One of its squadrons was the first ADC unit to fly the McDonnell F-101 Voodoo. It was discontinued after the 58th Fighter-Interceptor Squadron moved in 1959, leaving only a single fighter squadron at Otis.