The Town of Westminster is a suburban hill town which was originally the six-square mile Narragansett Township Number 2, granted to veterans and heirs of veterans of King Philip's War in 1728.  Used by Indians for hunting and fishing, the town was founded in 1733 although the first permanent settlement of the town didn't take place until 1737 and the community wasn't accepted as a town until 1770.  The community had been garrisoned as an outpost in the French and Indian Wars of the 1740's.  The initial grants to settlers were of 60-acre parcels and in the Colonial period the town fit the description of a poor agrarian community.  

By 1820, Westminster's diversity of religious affiliation was great enough to force the town to stop supporting a single minister with public taxes. There were Armianists, Unitarians, Congregationalists, Baptists, Methodists and Universalists in the town.  The community took a moderate position during Shays Rebellion, recommending release of the insurgents who had been captured but registering its opposition to the court system.

The new road to Fitchburg was built in 1835 and the Vermont and Massachusetts Railroad reached town in 1848. By 1900 there was East-West electric streetcar service established from Fitchburg to Gardner through Westminster center.  In the early 20th century, townspeople made chairs and manufactured paper while an unusually large influx of Finnish immigrants took over the old farms in town and settled in to an agricultural life.

Suburban development of the town on attractive lakeside sites and in sections of town with Wachusetts Mountain views has been part of its modern day growth.