Lisa Marie Simpson is a fictional main character in the animated television series The Simpsons. She is the middle child, and eldest daughter, of the eponymous family. She is voiced by Yeardley Smith and first appeared on television in The Tracey Ullman Show short "Good Night" on April 19, 1987. Lisa was created and designed by cartoonist Matt Groening while he was waiting in the lobby of James L. Brooks's office. Groening had been called to pitch a series of shorts based on Life in Hell but instead decided to create a new set of characters. He named the character after his younger sister Lisa Groening. After appearing on The Tracey Ullman Show for three years, the Simpson family got their own series on Fox, which debuted December 17, 1989.

At eight years of age, Lisa is the middle child of the Simpson family and eldest daughter of Homer and Marge, younger sister of Bart and elder sister of Maggie. She is highly intelligent, plays the saxophone, has been a vegetarian since the seventh season, has been a Buddhist since season thirteen and supports a number of different causes. She has appeared in other media relating to The Simpsons – including video games, The Simpsons Movie, The Simpsons Ride, commercials and comic books – and inspired an entire line of merchandise.