Andover is a town belonging to the Essex County in the US state of Massachusetts. It was settled in 1642 and was incorporated as town in 1646. As of the 2000 US census, the town of Andover had a population of 31,247 people. It belongs to the greater metropolitan area of Boston-Cambridge-Quincy, New Hampshire-Massachusetts. Part of Andover also belongs to the census designated place (CDP) of Andover.

The town is infamous with its involvement with the 1692 witch trials. Neighboring Salem, which was already conducting witch trial at time, influenced Andover and over 40 citizens in Andover were convicted as witches, most of them were women and children. The town was also one of the biggest anti-slavery supporters in the United States even before the start of the American Civil War.

The town is served by several major roads and by the Haverhill Boston Commuter Rail Line. The Merrimack Valley Regional Transit Authority provides local bus services for Andover.