Wallace Michael Shawn (born November 12, 1943) is an American actor, essayist, playwright, and screenwriter. He is known for playing Vizzini in The Princess Bride (1987), Mr. Hall in Clueless (1995), Dr. John Sturgis in Young Sheldon (2017–2024), and voicing Rex in the Toy Story franchise (1995–present).

Shawn also appeared in The Bostonians (1984), Prick Up Your Ears (1987), Scenes from the Class Struggle in Beverly Hills (1989), Vanya on 42nd Street (1994), My Favorite Martian (1999), The Double (2013), Maggie's Plan (2015), and Marriage Story (2019). He appeared in six Woody Allen films including Manhattan (1979), Radio Days (1987), and Rifkin's Festival (2020). His television work includes recurring roles as Jeff Engels in The Cosby Show (1987–1991), Grand Nagus Zek in Star Trek: Deep Space Nine (1993–1999), Cyrus Rose in Gossip Girl (2008–2012), and Father Frank Ignatius in Evil (2022–2024).

Shawn is also a playwright; his plays include the Obie Award–winning Aunt Dan and Lemon (1985), The Designated Mourner (1996) and Grasses of a Thousand Colors (2008). He wrote and starred, with Andre Gregory, in the 1981 avant-garde drama My Dinner with Andre, and played the title role in A Master Builder (2013), a film adaptation of Henrik Ibsen's play. Haymarket Books published his books Essays (2009) and Night Thoughts (2017).Wallace Shawn, licensed under CC-BY-SA, full list of contributors on Wikipedia.