Nancy Cartwright (b. 1957) is a voice actress best known as the voice of Bart Simpson on The Simpsons. She performed with her Simpsons co-stars in the celebrity version of "Monster in the Mirror."
Early in her voiceover career, she was mentored by Daws Butler, famous for his work with Hanna-Barbera. Her first animation voice role was playing Gloria on Hanna-Barbera's Richie Rich series. Some of her roles since then have included Rufus the naked mole-rat on Kim Possible, Mindy on Animaniacs, Margo Sherman on The Critic, and Chuckie Finster on Rugrats (taking over from Christine Cavanaugh in 2001).
In live-action, Cartwright has appeared in Twilight Zone: The Movie, the 1998 remake of Godzilla (with Simpsons co-stars Harry Shearer and Hank Azaria), Cheers, and The Fresh Prince of Bel-Air.