General Sir William Thompson Adair KCB (1850-1931) was a Royal Marine officer and Ulster Unionist.
Educated at Cheltenham, he entered the Royal Marine Light Infantry in 1867 and served in South Africa during the Second Boer War.
He was Deputy Adjutant-General, Royal Marines (1907-11).
Adair played a prominent role in the Ulster Unionist Party and was commander of the Antrim Ulster Volunteer Force.
In 1914, he took charge of the landing and dispersal of guns during the Larne gun-running.