William Barrett was born circa 1629 in England to Thomas Barrett (1609-1668) and Margaret Huntington (1608-1681) and died 17 March 1689 Cambridge, Middlesex County, Massachusetts of unspecified causes. He married Sarah Poole (1636-1661) 19 August 1656 in Cambridge, Middlesex County, Massachusetts. He married Mary Barnard (1639-1673) 16 June 1662 in Cambridge, Middlesex County, Massachusetts. He married Mary Sparhawk (1652-1673) 8 October 1673 in Cambridge, Middlesex County, Massachusetts. He married Margaret Bartlett (c1640-) 1676 in Cambridge, Middlesex County, Massachusetts.
Children
| Offspring of William Barrett and Sarah Poole (1636-1661) | |||
| Name | Birth | Death | Joined with |
| Lydia Barrett (1657-1682) | |||
| John Barrett (1660-) | |||
| Offspring of William Barrett and Mary Barnard (1639-1673) | |||
| Name | Birth | Death | Joined with |
| Mary Barrett (1663-) | |||
| William Barrett (1665-1733) | |||
| Edward Barrett (1668-) | |||
| Samuel Barrett (1669-1732) | 7 February 1669 Cambridge, Middlesex County, Massachusetts | 22 July 1732 Boston, Suffolk County, Massachusetts | Sarah Manning (1668-1742) |
| Bartholomew Barrett (1672-) | |||
| Offspring of William Barrett and Margaret Bartlett (c1640-) | |||
| Name | Birth | Death | Joined with |
| Margaret Barrett (1676-) | |||
| Thomas Barrett (1678-) | |||
| Bartholomew Barrett (1681-) | |||
| Lydia Barrett (1681-) | |||
