Sullivan Square  is a station on the MBTA rapid transit Orange Line, and a major bus transfer point. It was also a major transfer point on the old Charlestown Elevated, with two streetcar loops (one at elevated level and one at surface level) for free transfers, later converted for trackless trolleys and buses.

The first Sullivan Square station Opened on June 10, 1901, was located on the Charlestown Elevated, which last ran on April 4, 1975. It was replaced with the Haymarket North Extension which opened April 7,1975, including a new Sullivan Square Station, a bit west of the old one. The Station is Handicapped Accessible.