Amanda Peet (born January 11, 1972) is an American actress, writer and producer. She began her career with small parts on television, and made her feature film debut in Animal Room (1995). Her portrayal of Jill St. Claire in The Whole Nine Yards (2000) brought her wider recognition, and she has since appeared in a variety of films, such as Saving Silverman (2001), High Crimes; Changing Lanes; Igby Goes Down (all 2002), Something's Gotta Give (2003), Identity (2003), Melinda and Melinda (2004), A Lot Like Love (2005), Syriana (2005), Battle for Terra (2007), Martian Child (2008), The X-Files: I Want to Believe (2008), Please Give (2010), Gulliver's Travels (2010), The Way, Way Back (2013), Identity Thief (2013), and Trust Me (2013).

On television, Peet starred as Jacqueline Barrett on The WB's Jack & Jill (1999–2001), as Tina Morris on HBO's Togetherness (2015–2016), as Jules on IFC's Brockmire (2016–2020), and as Betty Broderick on the second season of Dirty John in 2020. She wrote and co-executive produced the Netflix series The Chair that was released in 2021.