"Even a man who is pure at heart, and says his prayers by night, may become a wolf when the wolfbane blooms and the autumn moon is bright." This quote has been listed in some sources as an authentic Gypsy or Eastern European folk saying. Writer Curt Siodmak admits that he simply made it up. Nonetheless, the rhyme would be recited in every future Universal film appearance of the Wolf Man, and would also be quoted in Van Helsing. (Albeit, slightly modified, "The moon is shining bright." rather than "The autumn moon is bright.")

Lon Chaney Jr.'s make-up took six hours to apply, and three hours to get off.

Dick Foran was originally cast in the role of Larry Talbot. He was replaced just one week before filming began.

Evelyn Ankers had a rough time on the set. Lon Chaney Jr. delighted in sneaking up on her in full makeup and scaring her senseless. In other deleted scene, a bear was to wrestle with the werewolf but broke loose, chasing the actress up into the soundstage's rafters.

Evelyn Ankers later recalled that during the filming of the final confrontation, she was required to faint, and then to stay on the floor until the fight scene between Lon Chaney Jr. and Claude Rains was finished. Ankers recalled that during one take, she stayed on the floor so long that the low-hanging chemical fog being used in the scene caused her to pass out. When the take was over, the film crew began rearranging the cameras and lights for the next take, not noticing that Ankers had not emerged from the floor. Finally someone on the crew realized that Ankers was missing, and she was pulled up from the fog and revived.

Maria Ouspenskaya, who played the old Gypsy woman, was only six years older than Bela Lugosi, who played her son.

Curt Siodmak's first draft lacked all werewolf scenes and the hallucinatory sequence.

According to the documentary on the Recent Wolf Man DVD collection, the script for The Wolf Man was influenced by writer Curt Siodmak's experiences in Nazi Germany. Siodmak had been living a normal life in Germany only to have it thrown into chaos and himself on the run when the Nazis took control, just as Larry Talbot finds his normal life thrown into chaos and himself on the run once he is turned into a werewolf. Also, the wolfman himself can be seen as a metaphor for the Nazis: an otherwise good man who is transformed into a vicious killing animal who knows who his next victim will be when he sees the symbol of a pentagram (i.e., a star) on them.

Despite Universal's apprehensions over the public's appetite for horror movies following the attack on Pearl Harbor, the film became one of the studio's top grossers in 1942.

In the first version of the script, Larry was not the prodigal son of Sir John Talbot, nor related to him in any way. He was an American engineer who comes to fix Sir John's telescope, and ends up getting trapped in the werewolf curse.

In this movie, we're told that a werewolf is "a human being who becomes a wolf at certain times of the year ... 'when the wolf-bane blooms and the autumn moon is bright,'" and the moon is never depicted in the film. This is the only one of the Universal series of Wolf Man films in which the full moon is never shown. In the sequel, the folklore is changed to "when the moon is full and bright."

It was originally given the working title, "Destiny," which had been the preliminary title of a number of Universal films that decade (including Son of Dracula).

Larry had been away 18 years working on Mt. Wilson Observatory in California.

Larry Talbot and his father Sir John attend church on Sunday in the village, but the doorway and steps of the village church looks more like that of a cathedral. In fact, it was a cathedral - part of the original set built for the legendary silent version of The Hunchback of Notre Dame, which had starred Lon Chaney Jr.'s famous father, Lon Chaney and which stood on the Universal back lot for over 20 years.

Larry Talbot's brother's name was John.

Larry's silver wolf-headed cane, the only known surviving prop from the movie, currently resides in the personal collection of genre film archivist Bob Burns. Burns, who was a schoolboy at the time, was given the cane head by the man who made it for the film, prop-maker Ellis Burman.

Many of the modern myths of werewolves originated from this film, such as a person becoming a werewolf through a bite, the only way to kill a werewolf is with a silver bullet, and changing into one during a full moon. These are original concepts created by writer Curt Siodmak.

Part of the original SHOCK THEATER package of 52 Universal titles released to television in 1957, followed a year later with SON OF SHOCK, which added 21 more features.

Shooting lasted from October 27-November 25, 1941, with a December 12 release.

Silent film actor Gibson Gowland appears in this film as a villager present at the death of Larry Talbot. He also had been present during the Phantom's death scene in the 1925 version of The Phantom of the Opera, becoming the only actor to appear in death scenes performed by both Lon Chaney and Lon Chaney Jr.