Theresa Lynn Russell (née Paup; born March 20, 1957) is an American actress. Russell made her film debut in The Last Tycoon (1976) directed by Elia Kazan, followed by a lead role opposite Dustin Hoffman in Straight Time (1978). She was then cast in Nicolas Roeg's controversial thriller Bad Timing (1980), which earned her critical praise. After marrying Roeg in 1982, she appeared in multiple films directed by him, mainly arthouse and experimental films, including Eureka (1983), Insignificance (1985), and Cold Heaven (1991).

Following lead roles in Ken Russell's Whore, Russell starred in Steven Soderbergh's Kafka, both released in 1991. Russell appeared in the box-office hit thriller Wild Things (1998), starred in the critically acclaimed drama The Believer (2001) and in the later 2000s, she appeared in HBO miniseries Empire Falls (2005), and had a minor role in Spider-Man 3 (2007).