Jessi Ruth Klein (born August 18, 1975) is an American writer, actress and stand-up comedian from New York City. Klein has regularly appeared on shows such as The Showbiz Show with David Spade and VH1's Best Week Ever and has performed stand-up on Comedy Central's Premium Blend. She provided commentary for CNN in the debates of the 2004 presidential election. A self-proclaimed "geek", Klein has appeared on the television specials for My Coolest Years: Geeks on VH1 and Rise of the Geeks on E!. Klein also provided the voice of Lucy in the animated pilot for Adult Swim's Lucy, the Daughter of the Devil.
Klein previously worked as a director of development for Comedy Central. Some of the shows she helped develop for the network were Chappelle's Show and Stella. She was the head writer and executive producer of Inside Amy Schumer.