Before the American Civil War, Massachusetts was a center for the abolitionist, temperance, and transcendentalist movements. In 2004, Massachusetts became the first U.S. state to legally recognize same-sex marriage as a result of the Massachusetts Supreme Judicial Court's decision in Goodridge v. Department of Public Health.

Massachusetts was originally inhabited by tribes of the Algonquian language family such as the Wampanoag, Narragansett, Nipmuc, Pocomtuc, Mahican, and Massachusett. While cultivation of crops like squash and corn supplemented their diets, these tribes were generally dependent on hunting, gathering and fishing for most of their food. Villages consisted of lodges called wigwams as well as longhouses, and tribes were led by male or female elders known as sachems.

The Wampanoag tribe maintains reservations at Aquinnah on Martha's Vineyard and at Mashpee on Cape Cod—with an ongoing native language revival project underway since 1993, while the Nipmuc maintain two state-recognized reservations in the central part of the state, including one at Grafton.

Massachusetts has avoided many forms of racial strife seen elsewhere in the US, but examples such as the successful electoral showings of the nativist (mainly anti-Catholic) Know Nothings in the 1850s, the controversial Sacco and Vanzetti executions in the 1920s, and Boston's opposition to desegregation busing in the 1970s show that the ethnic history of Massachusetts was not completely harmonious.