Originally was to be released in the summer of 2007 but was pushed back. Then after being pushed back a second time the film was finally released on May 30, 2008.
There is a scene when Merle Haggard's "Mama Tried" is played loudly on the home record player. The name of Merle Haggard's Band for that recording (and all others) was "The Strangers".
Liv Tyler suffered from tonsillitis during the shooting of the film.
The script for the film was originally titled "The Faces".
Even if only slightly, the camera shots are constantly moving as hand held cameras or steady cams were used for the entire film.
Star Liv Tyler said in the original script there was much more interaction and dialog between the victims and the villains during the finale. It was cut from the film though to keep the intruders more mysterious and eerie.
Bryan Bertino credits the main inspiration of the film to the infamous Manson murders.
According to director Bryan Bertino the film is partially based on an incident that happened to him as a child. One evening a stranger came to his door and asked for someone who wasn't there. The stranger left, but later Bertino found out that other homes in his neighborhood had been broken into that night.