Cast

Main article: List of Monsters, Inc. characters

• Billy Crystal as Michael "Mike" Wazowski
  • Noah Johnston as Young Mike^[6]
• John Goodman as James P. "Sulley" Sullivan
• Steve Buscemi as Randall "Randy" Boggs^[10]
• Joel Murray as Don Carlton, a middle-age returning student and the founding member of Oozma Kappa fraternity^[10][11]
• Sean Hayes as Terri Perry, an Oozma Kappa fraternity member who shares his brother's body.^[12][13]
• Dave Foley as Terry Perry, an Oozma Kappa fraternity member^[10][12][13]
• Peter Sohn as Scott "Squishy" Squibbles, an Oozma Kappa fraternity member^[10][12]
• Charlie Day as Art, an Oozma Kappa fraternity member^[12]
• Helen Mirren as Dean Abigail Hardscrabble, the chair of the Scarer program at Monsters University^[14]
• Alfred Molina as Professor Derek Knight^[15]
• Nathan Fillion as Johnny J. Worthington III, president of Roar Omega Roar^[16]
• Aubrey Plaza as Claire Wheeler, Greek Council president^[16]
• Tyler Labine as Brock Pearson, Greek Council vice-president^[16]
• John Krasinski as "Frightening" Frank McCay^[16]
• Bonnie Hunt as Ms. Karen Graves, Mike's grade school teacher^[16]
• Bill Hader as Referee, Slug^[17]
• Bobby Moynihan as Chet Alexander, a Roar Omega Roar fraternity member^[16]
• Julia Sweeney as Sherri Squibbles, Scott's mother^[10][16]
• Beth Behrs as Carrie Williams, leader of Python Nu Kappa sorority^[16]
• Bob Peterson as Roz^[17]
• John Ratzenberger as The Abominable Snowman, a Monsters, Inc. mailroom employee^[16][18]