Mary Hatch Bailey is a fictional character in Frank Capra's 1946 film It's a Wonderful Life. She is the sweetheart and later wife of protagonist George Bailey. Mary is played by Donna Reed as an adult and Jean Gale as a child. She is loosely based on Mary Pratt, a character in Philip Van Doren Stern's 1943 short story The Greatest Gift.

It's a Wonderful Life is a 1946 American Christmas supernatural drama film produced and directed by Frank Capra. It is based on the short story and booklet "The Greatest Gift" self-published by Philip Van Doren Stern in 1943, which itself is loosely based on the 1843 Charles Dickens novella A Christmas Carol. The film stars James Stewart as George Bailey, a man who has given up his personal dreams in order to help others in his community and whose thoughts of suicide on Christmas Eve bring about the intervention of his guardian angel, Clarence Odbody. Clarence shows George all the lives he touched and what the world would be like if he had not existed.