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, Nocturnal Animals, Keeping Up with the Joneses (all 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).