Terry Gilliam was afraid that Brad Pitt wouldn't be able to pull off the nervous, rapid speech. He sent him to a speech coach but in the end he just took away Pitt's cigarettes, and Pitt played the part exactly as Gilliam wanted.

In the first surface scene, the bear shot is reversed and, thus, it manages to completely inhale the condensation of its breath.

The film is introduced by the typing sound and sight of what are apparently excerpts from Dr. Kathryn Railly's notes on James Cole.

There are two releases of the film, by different companies, one from Arrow Video (released both in the US and UK) and the US Blu-ray by Universal. The Arrow release of this film contained a mistake in a scene about 40 minutes in. Bruce Willis's character is interrogated and the tracking shots and close-ups of the researchers questioning him are duplicated. This error was spotted by fans, who contacted Arrow Video to point it out. Arrow admitted the misprint, vowing to correct it (a similar problem was discovered in Arrow's 4K release of Henry: Portrait of a Serial Killer). Arrow issued this statement: "Sadly, we have identified a fault on our 12 Monkeys UHD disc (FCD2191/AV380), where at approximately 41 minutes some footage is briefly repeated with no interruption to the soundtrack. This error was not spotted by the producers, the facility that carried out the work or the filmmaker who approved the restoration. The fault was traced to the initial 4K data when one of the scanned reels contained some overlap in content and this wasn't flagged in the initial conform. We are continuing to review our workflow processes to prevent these issues from happening in the future. Please hold on to your copy and we will follow up with further information as soon as possible. Sorry for the inconvenience, we look forward to resolving this for you soon."

Featured in Siskel & Ebert: From Dusk Til Dawn/Eye for an Eye/12 Monkeys/Two If by Sea/Don't Be a Menace to South Central While Drinking Your Juice in the Hood (1996)