The Metropolitan State Hospital was an American public hospital for the mentally ill, located in the city of Waltham, Massachusetts. The Gaebler Children's Center for mentally ill youths was located on the grounds of the hospital.

It was closed in January 1992 as a result of the state's cost-cutting policy of closing its mental hospitals and moving patients into private care (see privatization). As of 2005, the large complex of buildings is being gradually demolished.

It should not be confused with the Metropolitan State Hospital in California.