Lieutenant General Marcus John Slade (22 January 1801 – 7 March 1872) was a British Army officer who became Lieutenant Governor of Guernsey.

Slade was the fourth son of General Sir John Slade, 1st Baronet (1762–1853) and the younger twin brother of Sir Frederic Slade, 2nd Baronet, who succeeded their father in the baronetcy.

[1] His youngest brother by his father's first wife was Admiral Sir Adolphus Slade.

[2] Slade was commissioned into the 75th Regiment of Foot in 1819.

[2] He was appointed Lieutenant Governor of Guernsey in 1859[4][5] and was also Colonel of the 50th (Queen's Own) Regiment of Foot from 1862 to his death in 1872.