The Keystone Building is a high-rise building located in downtown Boston, Massachusetts. The building stands at 400 feet (122 m) with 32 floors, and was completed in 1971. In height, it is tied with Harbor Towers I as the 27th-tallest building in Boston. The architectural firm who designed the building was Emery Roth & Sons. The Keystone Building is notable for its distinctive rounded corners and grooved façade.