Joseph O'Sullivan (25 January 1897 – 10 August 1922) along with Reginald Dunne, was a member of the Irish Republican Army, who shot dead Field Marshal Sir Henry Hughes Wilson on his doorstep at 36 Eaton Place in London on 22 June 1922. He was hanged for the killing on 10 August 1922 at Wandsworth Prison. The event provided the inspiration for the film Odd Man Out.