In 1971, she married Roy Boutling, and she had one son with him, Crispian Mills. She divorced from Roy Boutling in 1977. She also had another son, Jason Lawson, but from a different father - Leigh Lawson.
- 1960 - Pollyanna - Pollyanna
- 1961 - The Parent Trap - Susan Evers/Sharon McKendrick
- 1962 - In Search of the Castaways - Mary Grant
- 1963 - Summer Magic - Nancy Carey
- 1964 - The Moon-Spinners - Nicky Ferris
- 1965 - That Darn Cat! - Patti Randall
- 1981 - Disney Animation: The Illusion of Life - Herself
- 1986 - The Parent Trap II - Sharon Ferris/Susan Carey
- 1988 - Good Morning, Miss Bliss - Miss Carrie Bliss
- 1989 - The Parent Trap III - Susan Evers/Sharon Grand
- 1989 - The Parent Trap IV: Hawaiian Honeymoon - Susan Wyatt/Sharon Grand
- 2008 - The Age of Believing: The Disney Live-Action Classics - Herself
- Mills began her career thanks to Walt Disney's wife, Lillian, when she saw her in the movie, Tiger Bay.
- She was given her own collection of films, The Hayley Mills Collection, in which all of her Disney titles were re-released with new covers.
- According to the Disney's Wonderful World episode "Disney Animation: The Illusion of Life", Mills was originally going to provide Eilonwy's voice in The Black Cauldron, but that role ended up being taken by Susan Sheridan.