Massachusetts Senate's Norfolk and Plymouth district in the United States is one of 40 legislative districts of the Massachusetts Senate. It covers 18.9% of Norfolk County and 6.8% of Plymouth County population. Democrat John Keenan of Quincy has represented the district since 2011.

Quincy is a coastal U.S. city in Norfolk County, Massachusetts, United States. It is the largest city in the county and a part of Metropolitan Boston as one of Boston's immediate southern suburbs. Its population in 2020 was 101,636, making it the seventh-largest city in the state. Known as the "City of Presidents", Quincy is the birthplace of two U.S. presidents—John Adams and his son John Quincy Adams—as well as John Hancock, the first signer of the Declaration of Independence and the first and third governor of Massachusetts.