Louise Platt (August 3, 1915 – September 6, 2003) was an American theatre and film actress.
She is perhaps best remembered for her role as the pregnant officer's wife in John Ford's Stagecoach (1939). A Broadway star, she came to Hollywood in 1938 and returned to the stage in 1942 after the dissolution of her marriage to theatre director Jed Harris. She worked with Rex Harrison in Anne of the Thousand Days on Broadway in 1948 and in the 1950s played a variety of roles on television, including two appearances on Alfred Hitchcock Presents.