Johnny Mnemonic is a 1995 cyberpunk movie, loosely based on a short story of the same name by William Gibson, in which Keanu Reeves plays the title character, a man with a cybernetic implant in his brain designed to store information. It portrays Gibson's standard dystopian view of the future with the world dominated by large corporations and with strong East Asian influences.

The film was directed by Robert Longo on location in Canada, with Toronto and Montreal filling in for Newark, New Jersey and Beijing. A number of local monuments feature prominently, such as Toronto's Union Station and Montréal's Jacques Cartier Bridge.

The film is notable for the presence of Takeshi Kitano, whose role in the Japanese version of the film was greatly expanded.

Johnny is a data trafficker who has an implant that allows him to securely store data that is too sensitive for regular computer networks. His brain can carry nearly 80 gigabytes worth of data, or 160 gigabytes if he uses a doubler. Johnny uses this implant to act as a courier between contracting parties. On one delivery run, he accepts a package that not only exceeds the implant's safety limits (and will thus kill him if the data isn't removed in time), but also proves to contain information far more important and valuable than he had ever imagined. He has to get the data removed, and avoid being killed by assassins sent after him by the company who owns the data.

The story in the movie significantly deviates from the short story in parts, most notably turning Johnny, not girlfriend Molly, into the main action character. (In fact, the girlfriend character was transformed in the movie from Molly into "Jane", as the film rights to Molly were owned by a company not affiliated with the producers of this film.)

On its release, the movie was scorned by film critics, who mocked what they saw as mediocre acting, hardly-believable characters (including a drug-addicted dolphin and a hitman who patterns himself after Jesus Christ), and lack of substance/coherence. At one point in the film, Johnny loses his temper and launches into an infamously over-the-top, selfish tirade ("I want room service!") that earns the character as much derision as sympathy.

Despite this negative critical reaction, the film was nevertheless a modest success and could be considered influential on a number of subsequent films. Because it is considered to be one of the better portrayals of the cyberpunk genre, it is considered a cult classic by some fans.

During the scene where Johnny first uploads the data from the disc to his implant, and is subsequently attacked by the gangsters, the anime Demon City Shinjuku is seen showing on the screen in the background.

There are a few references to other films. One scene quotes the phrase "time to die" from Blade Runner (1982). In addition, the death and fake resurrection of the Street Preacher (who has a metal endoskeleton) is similar to various scenes in The Terminator (1984).