The Boston martyrs is the name given in Quaker tradition to the three English members of the Society of Friends, Marmaduke Stephenson, William Robinson and Mary Dyer, and to the Barbadian Friend William Leddra, who were condemned to death and executed by public hanging for their religious beliefs under the legislature of the Massachusetts Bay Colony in 1659, 1660 and 1661. Several other Friends lay under sentence of death at Boston in the same period, but had their punishments commuted to that of being whipped out of the colony from town to town.

Quakers are people who belong to the Religious Society of Friends, a historically Protestant Christian set of denominations. Members of these movements are generally united by a belief in each human's ability to experience the light within or "answering that of God in every one". Some profess a priesthood of all believers inspired by the First Epistle of Peter. They include those with evangelical, holiness, liberal, and traditional Quaker understandings of Christianity. There are also Nontheist Quakers, whose spiritual practice does not rely on the existence of God. To differing extents, the Friends avoid creeds and hierarchical structures. In 2017, there were an estimated 377,557 adult Quakers, 49% of them in Africa.