Fairhaven (Massachusett: Sconticut) is a town in Bristol County, Massachusetts, United States. It is located on the South Coast of Massachusetts where the Acushnet River flows into Buzzards Bay, an arm of the Atlantic Ocean. The town shares a harbor with the city of New Bedford, a place well known for its whaling and fishing heritage; consequently, Fairhaven's history, economy, and culture are closely aligned with those of its larger neighbor. The population of Fairhaven was 15,924 at the time of the 2020 census.

Fort Phoenix, owned by the Town of Fairhaven, is located in Fairhaven at the mouth of the Acushnet River, and it served, during colonial and revolutionary times, as the primary defense against seaborne attacks on New Bedford harbor. It is adjacent to the Fort Phoenix State Beach and Reservation operated by the state.

Prior to the second half of the nineteenth century, whale oil was the primary source of fuel for lighting in the United States. The whaling industry was an economic mainstay for many New England coastal communities for over two hundred years. The famous whaling port of New Bedford is located across the Acushnet River from Fairhaven. Fairhaven was also a whaling port; in fact, in the year 1838, Fairhaven was the second-largest whaling port in the United States, with 24 vessels sailing for the whaling grounds. The author of Moby-Dick, Herman Melville, departed from the port of Fairhaven aboard the whaleship Acushnet in 1841.