Sandys was the third and youngest, but only surviving, son of Sir Edwin Sandys (eldest son of Miles Sandys and nephew of Edwin Sandys, Archbishop of York) and his wife Elizabeth, daughter of William, 3rd Baron Sandys of The Vyne. Until their marriage in 1586, Sandys' parents were not related, their families having different origins: the family of Archbishop Sandys originated in Cumbria, while the Barons Sandys had their seat at The Vyne, Hampshire.
- William Sandys, 6th Baron Sandys
- Henry Sandys, 7th Baron Sandys
- Miles Sandys (died without offspring)
- Edwin Sandys, 8th Baron Sandys
- Hester Sandys, married Humphrey Noy, son of William Noy, Attorney General
- Alathea Sandys, married Francis Goston
- Mary Sandys, married Dr. Henry Savage, Master of Balliol College, Oxford
- Jane Sandys, married John Harris
- Margaret Sandys, married Sir John Mill
- Margery Sandys, married Sir Edmund Fortescue
Due to the Civil War, Sandys was never summoned to Parliament as a peer. Sandys fought on the royalist side, received a mortal wound at the Battle of Cheriton (at Bramdean near Alresford, Hampshire) on 29 March 1644, and died on 6 April.
|Family tree of Edwin Sandys, Archbishop of York|
- "SANDYS, Edwin I (c.1564-1608), of Eaton Bray, Beds". The History of Parliament. Retrieved 4 October 2019.
- Banks, T. C. (1808). The Dormant and Extinct Baronage of England. 2. p. 457. Retrieved 14 October 2019.
- Burke, J. & J. B. (1846). A General and Heraldic Dictionary of the Peerages of England, Ireland, & Scotland (3rd ed.). p. 464. Retrieved 14 October 2019.