Elizabeth Anne Caplan (born June 30, 1982) is an American actress. Her first acting role was on the television series Freaks and Geeks (1999–2000). She received wider recognition with roles in the films Mean Girls (2004) and Cloverfield (2008), she also starred on the television shows Related (2005–2006), The Class (2006–2007), and Party Down (2009–2010).

From 2013 to 2016, Caplan played Virginia E. Johnson on the Showtime series Masters of Sex, for which she received a nomination for the Primetime Emmy Award for Outstanding Lead Actress in a Drama Series. In 2019, she portrayed Annie Wilkes in the Hulu anthology series Castle Rock. Her other film appearances include Hot Tub Time Machine, 127 Hours (both 2010), Save the Date, Bachelorette (both 2012), The Interview (2014), Now You See Me 2, Allied (both 2016), and Extinction (2018). In 2022 she starred in FX on Hulu's Fleishman Is in Trouble (2022).