Nancy Jean Cartwright (born October 25, 1957) is an American actress. She is the long-time voice of Bart Simpson on the animated television series The Simpsons, for which she has received a Primetime Emmy Award for Outstanding Voice-Over Performance and an Annie Award for Best Voice Acting in the Field of Animation. Cartwright also voices other characters for the show, including Ralph Wiggum, Todd Flanders, Nelson Muntz, and Maggie. Wikipedia