John Montagu (21 August 1797 – 4 November 1853) was a British army officer and civil servant who served as Colonial Secretary of Van Diemen's Land from 1834 to 1842, and Colonial Secretary of the Cape Colony from 1843 to 1853.
Montagu is best known for his highly publicised dispute with Sir John Franklin, the famed polar explorer who held the office of Lieutenant-Governor of Van Diemen's Land at the time.
After Montagu's suspension from office by Franklin, he travelled to London and managed to successfully plead his case and find the necessary support to nullify his suspension.
Instead of a return to Van Diemen's Land, Montagu was offered the position of Colonial Secretary of the Cape Colony, which he accepted.
Franklin's subsequent removal from office meant he would be available for command of the Royal Navy's renewed attempt to complete the charting of the Northwest Passage, through the Arctic archipelago.
The Franklin expedition set out in 1845, and was never heard from again.