The film was shot over 2 days in May of 2011. The location used was lived in by a family of 4. Because of this, careful angles and camera movements had to be used to give the impression the character of Jenna was home alone.
Most of the beginning of the film was re-shot on day 2. Therefore in essence, almost the entire film was shot over 1 day.
Many scenes from the script had to be cut from the film while shooting because of time restraints.
The film was inspired from the first 20 minutes of the original "When a Stranger Calls" from 1979.