Isla Lang Fisher (; born 3 February 1976) is an Australian actress, voice actress, and author. Born to Scottish parents in Oman, she moved to Australia at age six. After appearing in television commercials at a young age, Fisher came to prominence for her portrayal of Shannon Reed on the soap opera Home and Away from 1994 to 1997, garnering two Logie Award nominations.
Fisher made a successful transition to Hollywood in the live-action film adaptation of Scooby-Doo (2002), and has since achieved fame for her roles in Wedding Crashers (2005), Confessions of a Shopaholic (2009), The Great Gatsby (2013), and Now You See Me (2013). Her other notable film credits include I Heart Huckabees (2004), The Lookout (2007), Definitely, Maybe (2008), Burke & Hare (2010), Bachelorette (2012), Visions (2015), Grimsby (2016); Keeping Up with the Joneses (2016), and Tag (2018). In addition, she has voiced characters in animated films such as Horton Hears a Who! (2008), Rango (2011), and Rise of the Guardians (2012). On television, she played a recurring role on the fourth and fifth seasons of Arrested Development (2013, 2018).