William Cage (28 March 1666 – 21 January 1738) was an English Tory politician who sat in the House of Commons of England from 1702 to 1705 and in the House of Commons of Great Britain from 1710 to 1715.
Cage was the son of William Cage, lawyer of Hollingbourne, Kent and his wife Cicely Culpeper, daughter of Sir Cheney Culpeper. His father and grandfather died in 1676 and 1677 and he succeeded to his grandfather's estate at Milgate Park. He was High Sheriff of Kent in 1694 but was fired from the justice's bench in December 1695 and arrested in February 1696 for betraying confidants. Nevertheless, he became a Deputy Lieutenant and a colonel of the militia by 1701.
At the 1701 election Cage stood for parliament at Rochester but was unsuccessful as a result of a smear campaign under the allegations of disloyalty. However he was elected Member of Parliament (MP) for Rochester in 1702 and sat until 1705 when following his defeat he was described as a "violent man". He was re-elected for Rochester again in 1710 in a Tory landslide and sat until 1715 when he declined to stand.
Caged died after a long retirement from politics aged 71.
Cage married Catherine before 1690 and had three sons and four daughters.