Simon Mark Monjack (9 March 1970 – 23 May 2010) was an English screenwriter, film director, and producer. He was the widower of American actress Brittany Murphy.
Monjack was born to Jewish parents in Hillingdon, Greater London. He grew up in Bourne End, Buckinghamshire. He attended Juniper Hill School, Flackwell Heath, then Royal Grammar School, High Wycombe. When he was 15, his father, William (1949–1986), died of a brain tumour in Oxfordshire. His mother Linda (née Hall), a hypnotherapist, lives in Bourne End.
Monjack directed, produced, and wrote the B-movie Two Days, Nine Lives in 2000. He received story credit for the 2006 biopic Factory Girl about Warhol actress/model Edie Sedgwick. Director George Hickenlooper contends that "Monjack had nothing to do with Factory Girl" and that "he filed a frivolous lawsuit against us making bogus claims that we had stolen his script. He held us literally to hostage and we were forced to settle with him as he held our production over a barrel." Monjack denied these claims. In 2007, E! News reported that Monjack was slated to direct a film adaptation of D. M. Thomas's novel about Sigmund Freud, The White Hotel, with Brittany Murphy cast in a leading role. The project never materialized.