According to director Steve McQueen, Colin Farrell (Jack Mulligan) and Robert Duvall (Tom Mulligan) improvised many of their scenes.
After a three-decade career playing more than 75 mostly supporting roles, this film marks Viola Davis's first lead role in a major studio movie.
First feature film directed by Steve McQueen that does not have Michael Fassbender in the cast. Fassbender had starred in McQueen's three previous movies: Hunger (2008), Shame (2011), and 12 Years a Slave (2013). Prior to this, McQueen had only directed short films.
Composer Hans Zimmer worked briefly on the original Widows (1983) television series on which this film is based, as an assistant to the show's composer Stanley Myers.
This film is based on the British television series Widows (1983). Director Steve McQueen began thinking about adapting the six-part crime drama into a film in 2012, while he was shooting Best Picture winner 12 Years a Slave (2013).