Marianne Wibberley (June 12, 1965, in California, USA) is an American screenwriter and film producer. Together with her husband Cormac Wibberley, she forms the well-known screenwriting duo The Wibberleys. They have been writing together since 1991 and sold their first screenplay in 1993. She studied at the University of California, Los Angeles (UCLA), where she earned both her bachelor's and master's degrees in film studies. In addition to her work as a screenwriter, she also teaches screenwriting at UCLA. Her most famous films include The 6th Day (2000), I Spy (2002), Charlie's Angels: Full Throttle (2003), Bad Boys II (2003), National Treasure (2004), The Shaggy Dog (2006), National Treasure: Book of Secrets (2007), and G-Force (2009). On television, she worked as a writer, creator, and executive producer on Common Law (2012) and National Treasure: Edge of History (2022). She lives with her husband and daughter in South Bay, Los Angeles.