Elizabeth Greer "Beanie" Feldstein (born June 24, 1993) is an American actress. She first gained recognition for her starring roles in the comedy film Neighbors 2: Sorority Rising (2016), the comedy-drama film Lady Bird (2017), and the coming-of-age comedy film Booksmart (2019), the latter of which earned her a nomination for the Golden Globe Award for Best Actress - Motion Picture Comedy or Musical.

Feldstein has appeared on the Broadway stage, making her debut as Minnie Fay in Hello, Dolly! (2017-18) and portraying the lead role of Fanny Brice in the first revival of Funny Girl (2022), a performance for which she earned a nomination for the Drama League Award for Distinguished Performance. In 2021, she portrayed Monica Lewinsky in the third season of the FX anthology series American Crime Story: Impeachment.