Kathleen Key (born Kitty Lanahan; April 1, 1903[citation needed] – December 22, 1954) was an American actress who achieved a brief period of fame during the silent era.

Born in Buffalo, New York, Key made her debut in the 1920 Australian film The Jackeroo of Coolabong, playing a lead role.

An early career highpoint was her selection as one of the 1923 WAMPAS Baby Stars; however, by the end of the decade Key had her last significant film role, as Colette in 1929's The Phantom of the North.

[citation needed] In the early 1930s, Key had a well-known love affair with silent-film actor Buster Keaton, who was married at the time.

As told in Marion Meade's biography of Keaton, the actor attempted to call off the relationship, but Key flew into a jealous rage and ransacked his MGM dressing room, which caused her to be virtually blacklisted afterward by the movie industry.