This is a list of Massachusetts county name etymologies:
- Barnstable County:
- Berkshire County: Berkshire is possibly named for the English county of Berkshire.
- Bristol County: Named for its county seat of Bristol, Massachusetts, which was in turn named for the English port city of Bristol. When Bristol joined Rhode Island, the name was kept.
- Dukes County: Formerly a part of Dukes County, New York until 1691. The land at one time was literally the possession of the Duke of York.
- Essex County: Essex is possibly named for the English county of Essex.
- Franklin County: Franklin is possibly named for Benjamin Franklin who was born and raised in Massachusetts.
- Hampden County: Hampden is possibly named for "The Patriot" John Hampden, the famous 17th century English parliamentarian.
- Hampshire County: Hampshire is possibly named for the English county of Hampshire.
- Middlesex County: Middlesex is possibly named for the English county of Middlesex.
- Nantucket County: Coterminous with the Town of Nantucket.
- Norfolk County: Norfolk is possibly named for the English county of Norfolk.
- Plymouth County: Plymouth County is named for its seat of Plymouth, which in turn is named for the English port city of Plymouth.
- Suffolk County: Suffolk is possibly named for the English county of Suffolk.
- Worcester County: Worcester is possibly named for the English region called Worcester.