Millie may refer to:
- A diminutive of the female given names "Emily", "Millicent", "Mildred", "Camilla" or sometimes "Amelia"
- millie, an affectionate or pejorative term for a young working-class woman
Millie may specifically refer to:
- Millie (film), a film by John Francis Dillon, starring Helen Twelvetrees
- Millie (singer), best known for "My Boy Lollipop"
- Millie (dog), dog owned by Barbara and George H. W. Bush
- Millie (short story), a short story by Katherine Mansfield
- Millie the Model, a comic book series and its titular character
- Millie (Suikoden) A character in the video game suikoden 2
- Millie the Echidna, one of the three official mascots of the 2000 Summer Olympic Games in Sydney
- Millicent Mudd, a character in the webcomic Ozy and Millie
- "A Milli" a single from Lil Wayne's sixth studio album, Tha Carter III
- Thoroughly Modern Millie, the 1967 musical film starring Julie Andrews
- Thoroughly Modern Millie (musical), the 2002 Broadway musical
- Millie, the main character in Catherine Cookson's novel The Rag Nymph, which has also been turned into a television series
- Millie, a character in the Warriors novel series
- Millie Burtonburger from Kid vs. Kat