The AEC Regent II was a front-engined double-decker bus built by AEC from 1945 to 1947. Despite officially being a new type it was very similar to the . The Regent IIs were all documented as being new with the A173 (also known as the 7.7-litre) engine and a four speed sliding mesh gearbox. The only vehicles that were not standard were the 100 purchased by B.M.M.O. (Birmingham & Midland Motor Omnibus Company), which were classified as O661/20 as the front had to be re-designed so they could carry similar bonnets and radiator grilles that B.M.M.O. had designed for the double deckers they built themselves.