William Armstrong Henry (6 September 1884 — after 1960) was a Scottish professional footballer who played as a right back for Rangers, Falkirk, Leicester City and Manchester City.^[1]

Henry was born in Glasgow^[2] and began his football career in Scotland with Rangers and then Falkirk before transferring to Leicester City in England in September 1909.^[2][3][4][5] He played 96 times for Leicester before Manchester City purchased him for £1,000 in 1911, the highest fee that Leicester City had received for one of their players at the time.^[2] He made his Manchester City debut in a 1–1 draw against Sunderland in November 1911.^[2] He went on to make 157 appearances for Manchester City in which he scored one goal.^[2] The war hindered his outings for City but he did spend eight years there, the majority of his career.^[2] He never got a first-team cap for Scotland, but did get international honours in a military game between England and Scotland at Everton's Goodison Park ground.^[6][7]

Henry served in the 5th Cavalry Reserve Regiment during the First World War.^[2]