They Killed Sister Dorothy is a 2008 documentary film about American-born Brazilian nun Dorothy Stang, who was murdered on February 12, 2005, in Anapu, a city located in the Amazon Rainforest. Directed by Daniel Junge, the film is narrated by Martin Sheen in the English version and by Wagner Moura in the Portuguese version.

The film traces the reasons of the murder of Dayton, Ohio, native Dorothy Mae Stang, a 73-year-old nun of the Sisters of Notre Dame de Namur order who fought for the preservation of the Amazon Rainforest in the Brazilian state of Pará. It also follows the trial of those convicted for murdering Stang.

The film received the Audience Award and the Competition Award at the 2008 South by Southwest Festival, where it had its worldwide premiere. In Brazil, where the film title received a literal translation, it premiered at the 2007 Rio de Janeiro Film Festival. It was also screened at the 32nd São Paulo International Film Fesival. It is planned to receive a nationwide release on February 13, 2009.

Sister Dorothy Mae Stang, S.N.D., (7 July 1931 – 12 February 2005) was an American-born, Brazilian member of the Congregation of the Sisters of Notre Dame de Namur. She was murdered in Anapu, a city in the state of Pará, in the Amazon Basin of Brazil. Stang had been outspoken in her efforts on behalf of the poor and the environment, and had previously received death threats from loggers and land owners.

Stang, born in Dayton, Ohio, US, but a naturalized Brazilian citizen, worked as an advocate for the rural poor beginning in the early 1970s, helping peasants make a living by farming small plots and extracting forest products without deforestation. She also sought to protect peasants from criminal gangs working on behalf of ranchers who were after their plots. Dot, as she was called by her family, friends and most locals in Brazil, is often pictured wearing a t-shirt with the slogan, "A Morte da floresta é o fim da nossa vida" which is Portuguese for "The death of the forest is the end of our life."

Nigel Noble is an English sound mixer, film director and producer. He won an Academy Award in 1982 for Close Harmony in the category of Documentary Short Subject. Seven years later his film Voices of Sarafina! was screened in the Un Certain Regard section at the 1989 Cannes Film Festival.