John Gideon Millingen (1782–1862) was a British army surgeon and author. He was the brother of James Millingen and an uncle of Julius Michael Millingen. Born in Westminster to parents of Dutch descent, Millingen was educated in Paris where he achieved his medical degree. He became an assistant surgeon in the British Army in 1802, serving in the Peninsular War and won a medal at Waterloo and the surrender of Paris. He retired in 1823 and was appointed as a physician to the military asylum at Chatham and Hanwell.