William John St Clair Anstruther-Gray, Baron Kilmany, MC PC (5 March 1905 – 6 August 1985) was a Scottish Conservative Party politician.
The only son of Col William Anstruther-Gray of Kilmany and Clayre Jessie Tennant, he was educated at Eton College and at Christ Church, Oxford, England. In 1934, he married Monica Helen only child of Geoffrey Lambton, 2nd son of 4th Earl of Durham.
He served as a Lieutenant in the Coldstream Guards from 1926–30, and with the Shanghai Defence Force in 1927–28.
He was elected as Unionist Member of Parliament (MP) for North Lanarkshire, in Scotland, in 1931, holding the seat until 1945. Until September 1939, he served as Parliamentary Private Secretary to Financial Secretary to the Treasury, and to Secretary for Overseas Trade, and latterly to Sir John Colville, Secretary of State for Scotland.
In September 1939, he rejoined the Coldstream Guards and served in North Africa, France and Germany with Coldstream Guards and Lothians and Border Horse. He was promoted to the rank of Major in 1942. He was awarded the Military Cross in 1943.