The language used by the aliens (clicking sounds) was created by rubbing a pumpkin.
After the feature film based on the Halo: Combat Evolved (2001) video game series (which was to have been directed by Neill Blomkamp) fell through, producer Peter Jackson went to Blomkamp and offered him $30 million to make whatever he wanted, although this would be Blomkamp's first feature as a director. The result is this film.
The title is a nod to a real place and a real incident. District 6 was a mixed race neighbourhood of Cape Town which the apartheid government demolished in 1966 to make room for white people.
Star Sharlto Copley had not acted before and had no intention of pursuing an acting career. He stumbled into the leading role as director Neill Blomkamp placed him on camera during the short film.
The idea of the prawns being obsessed with cat food came from two inspirations. In impoverished areas of Johannesburg, director Neill Blomkamp would see people selling cheese poofs and other snack foods out of large three-foot tall bags and wanted the aliens to have a similar cheap food. The decision to make them cat food came from one of the producers who used canned cat food to bait traps when fishing for prawns in Vancouver.
Neill Blomkamp: When Koobus is tracking Wikus' location, Neill Blomkamp is seen briefly saying Wikus' coordinates.