One Day is a 2011 romantic drama film directed by Lone Scherfig from a screenplay by David Nicholls, based on Nicholls' 2009 novel of the same name. It stars Anne Hathaway and Jim Sturgess, with Patricia Clarkson, Ken Stott and Romola Garai in supporting roles. It was released in the United States on 19 August 2011 by Focus Features and in the United Kingdom on 24 August 2011 by Universal Pictures. A television series adaptation of the same source novel, starring Ambika Mod and Leo Woodall was released on Netflix in 2024.

Lone Scherfig is a Danish film director and screenwriter. She has been involved with the Dogme 95 film movement. Scherfig's movies are generally romantic comedies, including her film One Day (2011), based on the David Nicholls's novel of the same name.