Nancy Campbell Cartwright (born October 25, 1957) is an American film and television actress, comedian and voice artist. She is best known for her long-running role as Bart Simpson on the animated television series The Simpsons. Cartwright voices other characters for the show, including Nelson Muntz, Ralph Wiggum, Todd Flanders, Kearney and Database.
Cartwright has voiced dozens of other animated characters, including Chuckie Finster in Rugrats and All Grown Up!, Rufus in Kim Possible, Mindy in Animaniacs, and Margo Sherman in The Critic.
She voices Casey Kelp from The Snorks in "Brian the Bachelor" and reprises her roles as Bart Simpson, Nelson Muntz, Ralph Wiggum and Todd Flanders in "The Simpsons Guy".