Lilli Cooper (b. March 4, 1990) is an American actress who plays Doc in Fraggle Rock: Back to the Rock. For Sesame Workshop, she provides voices for the series Mecha Builders.
Cooper was the standby for Elphaba in 2014 for the Broadway production of Wicked, and originated the role of Sandy Cheeks in the Broadway production of SpongeBob SquarePants which opened in 2017. In 2018, Cooper played Julie Nichols in the musical adaptation of the 1982 film Tootsie, receiving a nomination for a Tony Award for Best Actress in a Featured Role in a Musical for her performance.