Charlton is a town in Worcester County, Massachusetts, United States. The population was 12,981 at the 2010 census.
Charlton was first settled in 1735. It was established as a District separated from Oxford on January 10, 1755, and became a Town on August 23, 1775 by a law that made all Districts into Towns to help for the cause of the Revolutionary War. It was named after Sir Francis Charlton. During the 1800s, farming continued to be the major occupation, but woolen mills were being built along some of the town's brooks by the turn of the twentieth century.
According to the United States Census Bureau, the town has a total area of 43.8 square miles (113 km2), of which 42.5 square miles (110 km2) is land and 1.2 square miles (3.1 km2) (2.86%) is water.
The town is bordered on the west by Sturbridge; on the north by East Brookfield, Spencer and Leicester; on the east by Oxford; and on the south by Dudley and Southbridge.
Charlton is bisected by north–south Route 31, which runs through the historical villages of Charlton Center, Charlton City and Charlton Depot. North-south Route 169 connects Charlton City with Southbridge.