Mary Jessica Gibbs is an American former child actress and voice actress who is best known for voicing Boo in the 2001 Disney/Pixar film, Monsters, Inc.. She also voiced Sha-Ron in Mulan II (2004). She is the daughter of storyboard artist Rob Gibbs and niece of composer Richard Gibbs.
Having been two years old at the time of filming for Monsters, Inc., the crew found that Gibbs was unable to sit still in the recording booth, and so they followed her around the studio with a microphone to record her dialogue.
Archive recordings of her cries and screams were re-used for toddler-age Riley Andersen in Inside Out, which was also directed by Pete Docter. In the video game, Kingdom Hearts III, archive recordings of her were used again for Boo.