The Vanishing Legion is a 1931 American pre-Code Western film serial from Mascot, directed by Ford Beebe and B. Reeves Eason.

Stars Harry Carey and Edwina Booth were originally intended to be in the studio's previous serial, King of the Wild, but had to be re-cast when the MGM film Trader Horn (1931) overran its schedule.

Both also starred in the Mascot serial The Last of the Mohicans and Carey was the lead in The Devil Horse.

An infection received while filming Trader Horn led to Booth's retirement from acting.

Jimmie Williams' father, Jed (Edward Hearn), has been framed for murder.