A. H. Weiler of The New York Times called it "a whodunit that raises the question as to why was it made". Variety called the film "a bloody, senseless kill-for-kicks feature, [that] exploits unnecessary violence in a university sorority house operated by an implausibly alcoholic ex-hoofer. Its slow-paced, murky tale involves an obscene telephone caller who apparently delights in killing the girls off one by one, even the hapless house-mother". Gene Siskel of the Chicago Tribune gave the film 1.5 stars out of 4 and called it a "routine shocker" that "is notable only for indicating the kind of junk roles that talented actresses are forced to play in the movies".

Kevin Thomas of the Los Angeles Times was more favorable, noting: "Before it maddeningly overreaches in a gratuitously evasive ending, Black Christmas... is a smart, stylish Canadian-made little horror picture that is completely diverting... It may well be that its makers simply couldn't figure out how to end it".

Modern assessment

Heidi Martinuzzi of Film Threat called the film "innovative" and praised the leading actresses, Olivia Hussey and Margot Kidder. TV Guide awarded the film three out of four stars, writing: "Although strictly standard fare, the material is elevated somewhat through Clark's skillful handling of such plot devices as obscene phone calls from the killer to the girls via the upstairs phone and a nicely handled twist ending, which provides a genuine shock".

Author and film critic Leonard Maltin gave the film two and a half out of four stars calling it "bizarre" but also praised Kidder's performance as a standout. The Time Out film guide noted that the film "manages a good slice of old-fashioned suspense".

Accolades

{| class="wikitable plainrowheaders sortable"

|-

! scope="col" style="width:15em;"| Award/association

! scope="col" style="width:2em;"| Year

! scope="col" style="width:20em;"| Category

! scope="col"| Recipient(s) and nominee(s)

! scope="col"| Result

! scope="col" class="unsortable"|

|-

! scope="row" rowspan="3"| Canadian Film Awards

| rowspan="3"| 1975

| Best Feature Film

| Black Christmas

|

| style="text-align:center;"|

|-

| Best Sound Editing in a Feature

| Kenneth Heeley-Ray

|

| style="text-align:center;"|

|-

| Best Performance by a Lead Actress

| Margot Kidder

|

| style="text-align:center;"|

|-

! scope="row"| Edgar Allan Poe Awards

| 1976

| Best Motion Picture

| rowspan="2"| Black Christmas

|

| style="text-align:center;"|

|-

! scope="row"| Saturn Awards

| 1975

| Best Horror Film

|

| style="text-align:center;"|

|-

|}

Legacy

Black Christmas gained a cult following in the years after its original release, and is widely regarded by critics and film historians as one of the earliest slasher films. It went on to inspire other slasher films, particularly John Carpenter's Halloween (which was apparently inspired by Clark suggesting what a Black Christmas sequel would be like).

Black Christmas has been included in multiple lists in various media outlets as one of the greatest horror films ever made. The film ranked No. 87 on Bravo<nowiki>'</nowiki>s The 100 Scariest Movie Moments. It was ranked at No. 67 in IndieWires The 100 Best Horror Movies of All Time, its entry stating that "the plot sounds formulaic, but Black Christmas remains timeless thanks to its terrifying and elusive killer, 'Billy', whose backstory is never revealed, as well as a foreboding ending that doesn't offer much hope for the film's Final Girl". Thrillist's Scott Weinberg, in his article The 75 Best Horror Movies of All Time, ranked the film at No. 48. Paul Schrodt of Esquire placed the film at No. 23 in his list of the 50 Best Horror Films of All Time. In 2017, Complex magazine named Black Christmas the 2nd-best slasher film of all time. The following year, Paste listed it the 3rd-best slasher film of all time, while also placing the character Jess Bradford at #1 in their list of "20 Best 'Final Girls' in Horror Movie History".

While director Clark maintained he did not intend for the film to have political leanings, critics have noted Black Christmas is nonetheless a feminist film for its treatment of female characters—particularly Jess having agency and making the choice to have an abortion—and its portrayal of casual misogyny (as when the police initially fail to take the sorority's concerns about the phone calls and Clare's absence seriously). Film critic Tim Dirks of the film-review website Filmsite.org added the film to his list of films featuring the "Greatest Film Plot Twists, Film Spoilers and Surprise Endings", based on the film's major plot twists – the revelation that the real killer was hidden inside the unsearched attic, and Jess' implied murder.

Hussey told Bravo during an interview about their 100 Scariest Movie Moments series, that when she met Steve Martin for the first time, he told her that she starred in one of his favorite films of all time. Hussey initially thought he was referring to Romeo and Juliet, but was surprised when Martin said it was Black Christmas and that he had seen the film 27 times.

Novelization

A novelization of the film written by Lee Hays was published in 1976 by Popular Library. The book follows roughly the same plot, but sticks with Roy Moore's original script. Because of this, the novel ends up fleshing out the characters more, adding scenes and lines of dialogue that were initially cut from the film's final script, and giving the Pi Kappa Sigma sorority more backstory.

Remakes

Black Christmas has been remade on two separate occasions, with the films differing significantly from the original.

The first remake was written and directed by Glen Morgan and was released on December 25, 2006, by Dimension Films and MGM Distribution Co. It is loosely based on the original film, containing more graphic content and a focus into the past of Billy. Andrea Martin was the only original cast member to appear in the film, and Clark served as an executive producer.

The second remake was directed and co-written by Sophia Takal, and starring Imogen Poots and Cary Elwes.

Fan films

A short fan film funded through an Indiegogo campaign was released on YouTube and Vimeo with the title It's Me, Billy, in 2021. It is billed as an "unofficial sequel" to the original film and is set fifty years after the original, following the granddaughter of Jess Bradford. The film was written, produced, and directed by Dave McRae and Bruce Dale and acts as a concept for a feature film as well as the first part of a two-part story.

In 2023, crowdfunding for It's Me, Billy Chapter 2 started on Indiegogo and that Olivia Hussey and Lynne Griffin, who starred in Black Christmas, were in the cast. Once again directed by Canadian filmmakers Dave McRae and Bruce Dale, Chapter 2 is a direct sequel to It's Me, Billy (2021) picking up immediately where that film ended. However, Hussey pulled out of the project for health reasons and was replaced by Lisa Kovack. It's Me, Billy Chapter 2 was released on October 11, 2024, to commemorate the 50th anniversary of when the original Black Christmas was first released in Canada.