Old Colony may refer to one of the following:
Plymouth Colony, the first permanent English colony in New England, on land that is now part of the U.S. state of Massachusetts Old Colony Historical Society in Taunton, Massachusetts Old Colony Housing Project in Boston, Massachusetts Old Colony League, a high school athletic conference in Massachusetts Old Colony Memorial, a weekly newspaper based in Plymouth, Massachusetts Old Colony Railroad, in operation in southeastern Massachusetts during 1845–1893 Old Colony Lines, branches of the MBTA commuter rail system in Massachusetts Old Colony Regional Vocational Technical High School, in Rochester, Massachusetts Old Colony Mennonites, a Mennonite group, many of which live across North America Old Colony Trust Co. v. Commissioner, a United States Supreme Court income tax decision