District 9 is a 2009 science fiction action film directed and co-written by Neill Blomkamp. The film stars Sharlto Copley, Jason Cope, and David James, and was adapted from Blomkamp's 2005 short film Alive in Joburg. The film is partially presented in a mockumentary format by featuring fictional interviews, news footage, and video from surveillance cameras. It begins in an alternate 1982, when an alien spaceship appears over Johannesburg, South Africa. When a population of diseased and malnourished insectile and crustaceous aliens are discovered on the ship, the South African government confines the asylum seekers to an internment camp called District 9. The title and premise of District 9 were predominantly inspired by events in Cape Town's District Six, during the apartheid era. The film explores themes of humanity, racism, xenophobia, social segregation, and medical torture.

District 9 premiered on 23 July 2009 at San Diego Comic-Con, and was released in New Zealand on 13 August, the United States on 14 August and South Africa on 28 August, by TriStar Pictures. It received positive reviews from critics, and was a financial success, earning $211 million on a budget of $30 million. It garnered numerous award nominations, including Academy Awards for Best Picture, Best Adapted Screenplay, Best Visual Effects, and Best Film Editing. The film is a co-production between the United States, New Zealand, and South Africa.

In 1982, an extraterrestrial mothership arrives and hovers over the South African city of Johannesburg. Inside, an investigation team finds over a million starved insectoid and crustacean-like aliens and the South African government voluntarily relocates the asylum seekers to a refugee camp called District 9. 28 years later, District 9 becomes both a ghetto and a shanty town, and humans come to view the aliens—derogatorily called "Prawns"—as filthy, violent animals who bleed resources from them. The Prawns have been systematically reduced to second-class citizens there and have been known to consume canned cat food.

Following unrest between the aliens and humans, the government hires the Multinational United (MNU), a large defense contractor, to forcibly relocate the extraterrestrials to a labour camp outside the city. Piet Smit, an MNU executive, appoints his son-in-law and MNU bureaucrat, Wikus van de Merwe, to lead the forced relocation. Meanwhile, three aliens, Christopher Johnson, his young son CJ, and Paul search a District 9 refuse dump for Prawn technology; Christopher has spent the last 20 years synthesizing fuel from their contents. They finally fill an entire container in Paul's shack as the relocation begins, but when Wikus comes to serve Paul a notice, he finds the hidden container and accidentally sprays some fuel into his face. Koobus Venter, a cruel MNU mercenary who is speciesist against the Prawns, kills Paul.

Wikus begins mutating into a Prawn, starting with his left arm that was injured after the exposure. He is taken to an underground MNU lab, where researchers discover his hybrid DNA grants Wikus the ability to operate Prawn weaponry, which is biologically restricted from humans. When there, Wikus discovers the grisly medical experiments, including vivisections the scientists were performing on the Prawns. Seeing the potential for profitable weapons research, Smit orders Wikus's organs to be harvested for genetic material. Wikus, however, overpowers the lab personnel and escapes. While Venter's forces hunt him, a fake news story is broadcast claiming Wikus is a wanted fugitive, who has contracted a contagious disease from copulating with extraterrestrials.

Wikus takes refuge in District 9, finding Christopher and the spaceship's command module dropship concealed underneath his shack. Christopher explains that the confiscated fuel is needed to reactivate the dropship, which can then dock with the mothership. This would allow Christopher to rescue his species and return home, and cure Wikus with the equipment onboard. Encouraged by a phone call from his wife, Tania, Wikus steals powerful alien weapons from Obasanjo, a Nigerian crime lord who believes that eating Wikus' alien arm will grant him alien abilities.

Wikus and Christopher attack the MNU and retrieve the fuel from the underground lab, where Christopher is horrified by the vivisections and other brutal medical experiments the MNU has performed on his species. Returning to the shack, Christopher decides that he must leave Earth immediately and return with help, therefore he must postpone curing Wikus's condition for up to three years. Unsatisfied with that answer, Wikus knocks Christopher unconscious and attempts to fly the module to the mothership, but Venter has it shot down. Venter captures Wikus and Christopher, but Obasanjo's gang ambushes them and abduct Wikus.

CJ, who remained hidden in the dropship, remotely activates the mother ship and a mecha alien battle suit in Obasanjo's base. The mecha suit guns down the Nigerian gangsters; Wikus enters the mecha suit and attempts to escape on his own. However, when he overhears Venter's order to kill Christopher, Wikus has a change of heart and returns to rescue Christopher from the mercenaries. Heading towards the dropship, the two come under heavy fire; Wikus decides to stay behind and fend off the mercenaries, buying time for Christopher and CJ to escape. Christopher promises to return and cure Wikus. After all of the other mercenaries are killed, Venter finally cripples the mecha suit, but several Prawns kill and dismember him before he can summarily execute Wikus. Christopher makes it into the dropship with CJ, and the dropship is levitated via a tractor beam back into the mothership, which finally leaves Earth.