The Wellesley Police Department started in April, 1893. Its first police officer, Harry M. Kingsbury was hired that November. By July of 1895, Kingsbury had been named the town's first police chief. In June of 1903, the department had acquired its first police station, located at the fire headquarters on Route 9. The police station's current headquarters on Washington Street was built in October 1996.

The department has 62 full-time employees, which include the chief, Terrence M. Cunningham, the deputy chief, three lieutenants, six sergeants, 35 officers (three of these positions are vacant and not funded), an animal control officer, 11 dispatchers, two secretaries, a records clerk and two custodians.