Based on the children's book series Basil of Baker Street by Eve Titus and Paul Galdone, the film is written and directed by John Musker, Dave Michener, Ron Clements, and Burny Mattinson.

Featuring the voices of Vincent Price, Barrie Ingham, Val Bettin, Susanne Pollatschek, Candy Candido, Diana Chesney, Eve Brenner, and Alan Young, the plot follows a mouse detective who undertakes to help a young mouse find and save her father from the criminal mastermind Professor Ratigan.

Sherlock Holmes also mentions "Basil" as one of his aliases in the Arthur Conan Doyle story "The Adventure of Black Peter".

The Great Mouse Detective was released to theaters on July 2, 1986, to positive reviews from critics and financial success, in sharp contrast to the box office underperformance of Disney's previous animated feature film, The Black Cauldron (1985).

David Q. Dawson, a retired army surgeon mouse newly returned from Afghanistan, meets Olivia and escorts her to Basil's residence.

Basil, Dawson and Olivia take Toby, Sherlock Holmes' pet Basset Hound, to trail Fidget's scent.

Ratigan then sets out for Buckingham Palace, where his henchmen hijack the royal guards' roles and kidnap the Mouse Queen.

After Basil, Dawson, and Olivia save Flaversham and the real Queen, they restrain Fidget and Ratigan's other henchmen, while Toby chases Felicia until she jumps over a wall, inadvertently into a pack of Royal Guard Dogs.

Veteran layout artist Joe Hale is credited with suggesting to adapt the children's book series Basil of Baker Street by Eve Titus, but the project fell into development limbo because of the similarities to The Rescuers.

The first idea for the victim was for Olivia—then an older and potential love interest whom Dawson falls for, but Miller suggested the character be "a little girl, someone they [the audience] can feel sorry for."

[13] The re-titling of the film proved to be unpopular with the filmmakers so much that animator Ed Gombert wrote a satirical interoffice memo, allegedly by studio executive Peter Schneider, which gave preceding Disney films generic titles such as Seven Little Men Help a Girl, The Wonderful Elephant Who Could Really Fly, The Little Deer Who Grew Up, The Girl with the See-through Shoes, Two Dogs Fall in Love, Puppies Taken Away, and A Boy, a Bear and a Big Black Cat.

"[3] Additionally, during one story meeting, Glen Keane decided to base the stature of Ratigan on then-Disney CEO Ron Miller,[22] who was a 6'6" former football player for the Los Angeles Rams.

"[23] The following supervising animators included Mark Henn for Basil, Hendel Butoy for Dawson, Rob Minkoff for Olivia, Andreas Deja for Queen Moustoria, Ruben Aquino for Mrs. Judson, and Mike Gabriel for Toby and Felicia.

Peraza's inspiration for the scene was a Japanese anime film, The Castle of Cagliostro (1979), the feature film debut of animator Hayao Miyazaki which is part of the Lupin III franchise; The Castle of Cagliostro, which Peraza was a fan of, featured a climactic scene involving characters amidst giant turning gears in a clock tower.

Eventually, Melissa Manchester was brought in; she wrote and performed "Let Me Be Good to You", by which the rough animation had to be re-timed and often re-animated to properly sync with the song.

[3] Mancini also co-wrote two of the film's three original songs, "The World's Greatest Criminal Mind" and "Goodbye So Soon" (both performed by Vincent Price).

[32] Following the theatrical re-release in February 1992, the film was released on VHS and Laserdisc in July 1992 as part of the Walt Disney Classics series.

On their syndicated television show, At the Movies, the film received a "two thumbs up" rating from critics Gene Siskel and Roger Ebert.

In his print review for The Chicago Tribune, Siskel enthusiastically praised the film as the most "truly memorable animated feature in 25 years" that "travels a wide emotional range, taking us from cuddly to scary, from recognition to wonder.

"[32] London's Time Out magazine wrote, "As usual with film noir [...] it is the villain who steals the heart and one is rooting for in the breathtaking showdown high up in the cogs and ratchets of Big Ben.

"[37] Nina Darnton of The New York Times applauded that "[t]he heroes are appealing, the villains have that special Disney flair – humorous blackguards who really enjoy being evil – and the script is witty and not overly sentimental.

"[39] Alex Stewart reviewed The Great Mouse Detective for White Dwarf #83, and stated that "After their dismal fudge of The Black Cauldron, it's good to see the Disney studios taking a step, however cautious, towards the world of animation as it is today.

The style is looser and more vigorous, and, in a climactic fight inside Big Ben, effectively amalgamates computer-drawn clockwork with hand-drawn characters.

The website's consensus states that "The Great Mouse Detective may not rank with Disney's classics, but it's an amiable, entertaining picture with some stylishly dark visuals.

[2] Its inexpensive success after its predecessor's under-performance gave the new management of Disney confidence in the viability of their animation department, though it was surpassed at the box office by An American Tail.

[51] In 2022, Rapunzel's Tangled Adventure, Monsters At Work and Wish alumni Tom Caulfield revealed that he alongside The Ghost and Molly McGee creators Bill Motz and Bob Roth pitched a crossover series featuring The Rescuers and The Great Mouse Detective at Disney Television Animation.

The series would have featured the descendant of Basil working at a modern version of The Rescue Aid Society more akin to The Kingsman or Mission: Impossible lead by Bianca.