Trivia

In 1986, Olivia Hussey met producers for the film Roxanne (1987), since they were interested in casting her for the title role. Roxanne co-star Steve Martin met her and said "Oh my God, Olivia, you were in one of my all-time favorite films." Thinking it was Romeo and Juliet (1968), Olivia was surprised to find out it was actually Black Christmas (1974). Martin claimed he had seen it around 27 times.

NBC scheduled this film for its prime-time network debut on January 28, 1978 under the title "Stranger in the House." On January 15th, 1978, two female students at Florida State University were murdered by an assailant who broke into the sorority house where they lived. Three other young women in the immediate vicinity were attacked and assaulted. NBC received numerous pleas from locals to pull the movie from broadcast in light of the crimes, and after first stating that they would offer the local affiliates an alternative movie to broadcast, they decided to just pull the plug on the movie altogether. Instead, the film "Doc Savage: Man of Bronze" was shown. NBC instead ran "Stranger in the House" as a late movie on May 14th the same year. The perpetrator of the crimes at Florida State University was later identified as serial killer Ted Bundy.

According to director Bob Clark the original script for the film featured murder scenes that were more graphic. Clark, however, felt that it would be more effective if the murders were toned down and kept subtle on screen. Writer Roy Moore liked the idea as well.

The audio for the demented phones calls was edited into the film during post-production. While shooting the footage for the phone call scenes the actresses were actually just reacting to threatening dialog being spoken from director Bob Clark from off-camera.

The film is regarded as being one of the first slasher films (with The Texas Chain Saw Massacre (1974), A Bay of Blood (1971), Psycho (1960), and Peeping Tom (1960) preceding this film). It set the layout for films such as John Carpenter's Halloween (1978). However, director Bob Clark considered it to be more of a psychological horror film than a slasher film.

Gerry Arbeid: Co-producer as the cab driver that arrives to pick up Mrs. Mac.

Debi Weldon: , who worked on the costume department of the film, uncredited as one of the sorority sisters.