The Province of Massachusetts Bay is a crown colony in British North America and one of the thirteen original states of the United States from 1776.

It is chartered on October 7, 1691 by William and Mary, the joint monarchs of the kingdoms of England, Scotland, and Ireland.

The charter takes effect on May 14, 1692, and includes the Massachusetts Bay Colony, the Plymouth Colony, the Province of Maine, Martha's Vineyard, Nantucket, Nova Scotia, and New Brunswick.

The modern Commonwealth of Massachusetts is the direct successor.

Maine has been a separate U.S. 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.

The name has been translated as "at the great hill", "at the place of large hills", or "at the range of hills", with reference to the Blue Hills and to Great Blue Hill in particular.