Channel Hop: In North America, this film has always been with Disney; however, in most international territories, it was originally released in theatres by Warner Bros., and in other international territories this was handled by United International Pictures. This is due to output deals Disney made for international theatrical distribution.
Divorced Installment: Originally this movie was going to be a pseudo-sequel/spin-off of The Rescuers that followed Penny after she was adopted. You can still see some traces of it, namely the main character's name being changed to "Jenny" and both films being set in New York City. The idea of a sequel to The Rescuers eventually came to fruition with The Rescuers Down Under, though it focuses on Bernard and Miss Bianca's continuing adventures instead of Penny's new life.
Dueling Movies: The 1980s were a very tumultuous time in animation. Don Bluth had very publicly split with Disney and started his own studio, which naturally was in competition with Disney. Oliver had two rivals from Bluth: The Land Before Time, which came out on the same day; and All Dogs Go to Heaven, released the following year but also featuring a roguish talking dog and a heartwarming little girl. Oliver did better than either in theaters (though "Time" had the higher opening weekend and worldwide gross), though it's now a somewhat forgotten member of the Disney canon while The Land Before Time and All Dogs Go To Heaven went on to spawn long-running video franchises.
Non-Singing Voice: Jenny Foxworthy and Rita (voiced respectively by Natalie Gregory and Sheryl Lee Ralph) each had a singing double (respectively Myhanh Tran and Ruth Pointer).
So My Kids Can Watch: Billy Joel took the role of Dodger because he had just had a daughter and wanted to be involved something she could connect with immediately.
Throw It In!: Dom DeLuise loved the role of Fagin immensely to the point that he improvised several lines, which were kept in the film.
Troubled Production: Oliver & Company got off to a bumpy start, first by having its budget drastically reduced as a result of the spectacular box-office failure of The Black Cauldron, and then having one of its co-directors, Peter Young, die barely a month into production. Richard Rich, one of the co-directors of The Black Cauldron and The Fox and the Hound, was put on the project to replace Young, but busied himself feuding with the new Disney management rather than actually getting anything useful done, resulting in him being fired from the company altogether. Things smoothed out once the remaining co-director, George Scribner, was allowed to take over as sole director and the film ultimately was a box-office success in spite of opening in fourth place against The Land Before Time, as it was the first ever animated film to make over 100 million dollars and it's success did prompt Disney's Senior Vice President of Animation, Peter Schneider, to announce the company's plans to release animated features annually. Though despite this it has since received little attention among the wider Disney canon. It was also an entry point for many future Disney and Pixar (and, by extension, DreamWorks) veterans who managed to break into the industry by working on this movie, meaning that it did at least help lead to longer-term success for the company.
The film was originally meant to be much darker, with the opening scene featuring Roscoe and Desoto killing Oliver's parents and him wanting to get revenge as a result.
Oliver was initially conceived as a rare and valuable Asian cat, which wouldve been the reason why Fagin kept him in the gang to pay off his debts.
Early concept art shows that Dodger was a puppy (basically the same age as Oliver) but he was aged up to match with the appearance of the more grown up actors like Billy Joel.
Concept art also shows that there were some cats in the gang of dogs but they were scrapped or changed into dogs themselves to not drive attention away from Oliver.
Jenny was originally a boy named Jimmy.
One of the early subplots considered was Fagin planning a heist to steal a rare valuable baby panda from the Central Park Zoo, but this was scrapped to keep it accurate to the original story.
Sykes was originally going to be The Faceless, à laDr. Claw, but the producers were forced to abandon that idea when the story development for the climax called for more physical action and involvement on Sykes' part.
Marlon Brando was offered the role of Sykes by Michael Eisner himself. Brando, however, turned it down, fearing the movie would bomb.