The Massachusetts Bay Colony (1628 – 1691), more formally the Colony of Massachusetts Bay, was an English settlement on the east coast of North America around the Massachusetts Bay, the northernmost of the several colonies later reorganized as the Province of Massachusetts Bay. The lands of the settlement were in southern New England, with initial settlements on two natural harbors and surrounding land about 15.4 miles (24.8 km) apart—the areas around Salem and Boston, north of the previously established Plymouth Colony. The territory nominally administered by the Massachusetts Bay Colony covered much of central New England, including portions of Massachusetts, Maine, New Hampshire, and Connecticut.

The Massachusetts Bay Colony was founded by the owners of the Massachusetts Bay Company, including investors in the failed Dorchester Company, which had established a short-lived settlement on Cape Ann in 1623. The colony began in 1628 and was the company's second attempt at colonization. It was successful, with about 20,000 people migrating to New England in the 1630s. The population was strongly Puritan and was governed largely by a small group of leaders strongly influenced by Puritan teachings. It was the first slave-holding colony in New England, and its governors were elected by an electorate limited to freemen who had been formally admitted to the local church. As a consequence, the colonial leadership showed little tolerance for other religious views, including Anglican, Quaker, and Baptist theologies.

The colonists had good relationships with the local Indians; however, they did join their neighbor colonies in the Pequot War (1636–38) and King Philip's War (1675–78). After that, most of the Indians in southern New England made peace treaties with the colonists or were sold into slavery after King Philips's War (apart from the Pequot tribe, whose survivors were largely absorbed into the Narragansett and Mohegan tribes following the Pequot War).

The Massachusetts Bay Colony was economically successful, trading with England, Mexico, and the West Indies. In addition to barter, transactions were done in English pounds, Spanish "pieces of eight", and wampum in the 1640s. In 1652, a currency shortage prompted the colony to authorize silversmith John Hull to issue coinage, now known as the oak tree, willow tree, and pine tree shillings.

Political differences with England after the English Restoration led to the revocation of the colonial charter in 1684. King James II established the Dominion of New England in 1686 to bring all of the New England colonies under firmer crown control. The Dominion collapsed after the Glorious Revolution of 1688 deposed James, and the Massachusetts Bay Colony reverted to rule under its revoked charter until 1691, when a new charter was issued for the Province of Massachusetts Bay. This new province combined the Massachusetts Bay territories with those of the Plymouth Colony and proprietary holdings on Nantucket and Martha's Vineyard. Sir William Phips arrived in 1692 bearing the charter and formally took charge of the new province.