The Province of Massachusetts Bay was a colony in New England which became one of the thirteen original states of the United States. It was chartered on October 7, 1691, by William III and Mary II, the joint monarchs of the kingdoms of England, Scotland, and Ireland, and was based in the merging of several earlier British colonies in New England. The charter took effect on May 14, 1692, and included the Massachusetts Bay Colony, the Plymouth Colony, the Province of Maine, Martha's Vineyard, Nantucket, Nova Scotia, and New Brunswick; the Commonwealth of Massachusetts is the direct successor. Maine has been a separate state since 1820, and Nova Scotia and New Brunswick are now Canadian provinces, having been part of the colony only until 1697.

The name Massachusetts comes from the Massachusett Indians, an Algonquian tribe. It has been translated as "at the great hill", "at the place of large hills", or "at the range of hills", referencing the Blue Hills and Great Blue Hill, respectively.

Colonial settlement of the shores of Massachusetts Bay began in 1620 with the founding of the Plymouth Colony. Other attempts at colonization took place throughout the 1620s, but expansion of English settlements only began on a large scale with the founding of the Massachusetts Bay Colony in 1628 and the arrival of the first large group of Puritan settlers in 1630. Over the next ten years, there was a major migration of Puritans to the area, leading to the founding of a number of new colonies in New England. By the 1680s, the number of New England colonies had stabilized at five: the Connecticut Colony, the Colony of Rhode Island and Providence Plantations, and the Province of New Hampshire all bordered the area surrounding Massachusetts Bay and Plymouth. Massachusetts Bay, however, was the most populous and economically significant, hosting a sizable merchant fleet.

The colonies had struggles with some of the Indigenous inhabitants. The Pequot tribe was virtually destroyed in the Pequot War during the 1630s, and King Philip's War in the 1670s decimated the Narragansetts in southern New England. King Philip's War was also very costly to the colonists of New England, putting a halt to expansion for several years.

Massachusetts and Plymouth were both somewhat politically independent from England in their early days, but this situation changed after the restoration of Charles II to the English throne in 1660. Charles sought closer oversight of the colonies, and he tried to introduce and enforce economic control over their activities. The Navigation Acts passed in the 1660s were widely disliked in Massachusetts, where merchants often found themselves trapped and at odds with the rules. Charles II also viewed Massachusetts' issuing of coins as a treasonous act. However, many colonial governments did not enforce the acts themselves, particularly Massachusetts, and tensions grew when Charles revoked the first Massachusetts Charter in 1684.

In 1686, Charles II's successor James II formed the Dominion of New England which ultimately created a single political unit out of the British territories from Delaware Bay to Penobscot Bay. Dominion governor Edmund Andros was highly unpopular in the colonies, but he was especially hated in Massachusetts where he angered virtually everyone by rigidly enforcing the Navigation Acts, vacating land titles, appropriating a Puritan meeting house as a site to host services for the Church of England, and restricting town meetings, among other sundry complaints. James was deposed in the 1688 Glorious Revolution, whereupon Massachusetts political leaders rose up against Andros, arresting him and other English authorities in April 1689. This led to the collapse of the Dominion, as the other colonies then quickly reasserted their old forms of government.

The Plymouth colony never had a royal charter, so its governance had always been on a somewhat precarious footing. The Massachusetts colonial government was re-established but it no longer had a valid charter, and some opponents of the old Puritan rule refused to pay taxes and engaged in other forms of protest. Provincial agents traveled to London where Increase Mather was representing the old colony leaders, and he petitioned William III and Mary II to restore the old colonial charter. The king refused, however, when he learned that this might result in a return to the religious rule. Instead, the Lords of Trade combined the colonies of Plymouth and Massachusetts Bay into the Province of Massachusetts Bay. They issued a charter for the Province on October 7, 1691, and appointed William Phips as its governor.

The new charter differed from the old one in several important ways. One of the principal changes was inaugurated over Mather's objection, changing the voting eligibility requirements from religious qualifications to land ownership. The effect of this change has been a subject of debate among historians, but there is significant consensus that it greatly enlarged the number of men eligible to vote. The new rules required prospective voters to own £40 worth of property or real estate that yielded at least £2 per year in rent; Benjamin Labaree estimates that this included about three-quarters of the adult male population at the time. The charter also guaranteed freedom of worship, but only for non-Catholic Christians.