In the scene in which Moriarty (Leo McKern) is auctioning off the Redcliff Document to a Russian and a Frenchman, the Russian bids five thousand Rubles, which equals six hundred twenty-five pounds. The Frenchman then bids seven thousand Francs, which equals six hundred twenty-six pounds, only one pound more than the Russian bid.

Gene Wilder's character's first name, Sigerson, was an alias used by Sherlock Holmes during the period in which he was believed to have been killed by Professor Moriarty, in Sir Arthur Conan Doyle's short story "The Adventure of the Empty House".

Gene Wilder's directorial debut.

"Orville Sacker" is similar to "Ormond Sacker", the name used in Sir Arthur Conan Doyle's first draft of a Holmes story (in which "Sherrinford Holmes" was the original name of the famous detective).

Gene Wilder performed four duties on this movie. Wilder was the lead actor, Screenwriter, performer of songs, and Director.

The film's title and story set-up are an in-joke referring to Sherlock Holmes' older brother, Mycroft Holmes, who was introduced in Sir Arthur Conan Doyle's story "The Adventure of the Greek Interpreter", and described as Sherlock's intellectual superior. In Doyle's short story "The Adventure of the Bruce-Partington Plans", Sherlock described the British government's reliance on Mycroft's prodigious intellectual powers as follows: "You are right in thinking that he is under the British government. You would also be right in a sense if you said that occasionally he is the British government, Mycroft draws four hundred and fifty pounds a year, remains a subordinate, has no ambitions of any kind, will receive neither honour nor title, but remains the most indispensable man in the country."

Apparently, Gene Wilder asked Mel Brooks to direct this picture. Brooks declined, stating that he would find it difficult to direct a screenplay that wasn't his own conception. Gene Wilder said, "I couldn't get Mel to direct it." Brooks did say though that Wilder should go off and make this film, could call upon him day or night, and after making this movie, he better "come back home as soon as you're done!"

Gene Wilder, Marty Feldman, and Madeline Kahn appeared in Young Frankenstein (1974).

Aubrey Morris (Coach Driver) and Wolfe Morris (Frenchman) were brothers in real-life.

Early in the film, Sigerson is seen doing some sword play. In real-life, following his 1955 graduation from the University of Iowa, Gene Wilder was accepted at the Bristol Old Vic Theatre School in Bristol, England. After six months of studying fencing, Wilder became the first freshman to win the All-School Fencing Championship. He was often employed as a fencing instructor and choreographer on stage plays in which he was involved.

This movie is notable for its catchy and memorable "Kangaroo Hop" musical dance number.

Gene Wilder once said that this film was "a terrifying commitment".

Frequently appearing together in this film as Sigerson Holmes and Sergeant Orville Stanley Sacker, this movie marked the re-teaming of Gene Wilder and Marty Feldman who had played Dr. Frankenstein and his assistant Igor in Mel Brooks' Young Frankenstein (1974).

Although Roy Kinnear's character is unnamed in the credits (as Moriarity's Assistant) and throughout most of the movie, he is addressed once by Moriarity as "Finney". Wilder chose Kinnear for the role because the two had formed a friendship during the making of Willy Wonka & the Chocolate Factory (1971), in which Wilder played Willy Wonka and Kinnear played Mr. Salt, Veruca's father.

All of main actors and actresses in this movie have now died. Gene Wilder died in 2016, Madeline Kahn died in 1999, Marty Feldman died in 1982, Dom DeLuise died in 2009, and Leo McKern died in 2002. Most of the supporting cast has also died.

John Le Mesurier appeared in The Hound of the Baskervilles (1959).

Douglas Wilmer played Sherlock Holmes in two previous productions - the first season of the TV series Sherlock Holmes (1964) and in an episode of the TV series Detective (1964).

In Sir Athur Conan Doyle's original Sherlock Holmes stories, Sherlock did not have a younger brother, but did have an older brother, Mycroft.

During his audio commentary, Gene Wilder mentions his screenplay was inspired by three of Arthur Conan Doyle's Sherlock Holmes stories. He identifies "The Adventure of the Empty House" and "The Adventure of the Naval Treaty" but can't remember the third title. That third title is "The Second Stain", which centers on the theft of a secret diplomatic document.

Moriarty's brass microscope (at 21:37) appears to be identical to that of Holmes in the British Granada series of 1984-1994 (starring Jeremy Brett).

One of several 1970s Sherlock Holmes satires and comedies. The movies include The Private Eyes (1980) (based on), They Might Be Giants (1971), The Seven-Per-Cent Solution (1976), The Hound of the Baskervilles (1978), The Private Life of Sherlock Holmes (1970), The Adventure of Sherlock Holmes' Smarter Brother (1975), The Return of the World's Greatest Detective (1976), It's a Mystery, Charlie Brown (1974), and The Strange Case of the End of Civilization as We Know It (1977).

Mel Brooks: As the voice of departing assassin after choosing the "lady" door over the "tiger" door, only to discover they're both tiger doors.

Albert Finney: At the start of the opera sequence, he has a sentence about the quality of the opera singers.

Richard Roth: Moriarty's assistant.