The Scarlet Letter is a 2004 South Korean erotic thriller film about a police detective who investigates a murder case while struggling to hang onto his relationships with his wife and mistress. The film's title is taken from the 1850 novel of the same name. It is the second film by La Femis-graduate and academic Byun Hyuk (Daniel H. Byun) after the Dogme 95 film Interview (2000), and starred Han Suk-kyu, Lee Eun-ju, Sung Hyun-ah and Uhm Ji-won. The film debuted as the closing film of the Pusan International Film Festival in 2004. The film is based on novelist Kim Young-ha's short stories A Meditation On Mirror and Photo Shop Murder.

The Scarlet Letter was released in October 28, 2004 on South Korea. The film was Lee's last feature-length acting performance before her death in February 2005.