Mary Caldwell may refer to:
- Mary Cardwell Dawson (1894âÂÂ1962), American musician and teacher
- Mary Gwendolin Caldwell, Marquise des Monstiers-Mérinville (1863âÂÂ1909), American philanthropist and socialite
- Mary Hay (actress) (1901âÂÂ1957), American dancer, musical comedy- and silent screen actress, playwright, and Ziegfeld girl; born Mary Hay Caldwell
- Mary Letitia Caldwell (1890âÂÂ1972), American chemist
- Mary Tourtel (1874âÂÂ1948), née Caldwell, British artist and creator of the comic strip Rupert Bear