Westminster is a town in Windham County, Vermont, United States. The population was 3,178 at the 2010 census.
Westminster is Vermont's oldest existing town and was chartered in 1735 by the Province of Massachusetts Bay and was called New Taunton or Township Number One. The town did not have any permanent settlers in the area until 1751. New Hampshire settlers came in and the town was later incorporated in the Province of New Hampshire on November 9, 1752, becoming the third chartered town for New Hampshire, west of the Connecticut River that would become the future state of Vermont. Because of that, it is debatable with both Brattleboro and Bennington on what the true oldest town in the state is. The Court of Common Pleas of the County of Cumberland of the Province of New York was moved to the town of Westminster in 1772. It was the site of the Westminster massacre in March 1775, in which two men were killed attempting to prevent New York provincial officials from exerting their authority over the area in the long-running dispute over the New Hampshire Grants. On January 15, 1777, a group of Vermonters met in the Westminster courthouse to declare the independence of the Republic of New Connecticut (later renamed the Republic of Vermont).
According to the United States Census Bureau, the town has a total area of 46.1 square miles (119.5 km2), of which 46.1 square miles (119.3 km2) is land and 0.04 square mile (0.1 km2) (0.06%) is water.
Westminster is crossed by Interstate 91 (Exit 5 serves the town), U.S. Route 5, Vermont Route 121 and Vermont Route 123.
The New England Central Railroad has track rights through the town.