God Never Said That: No sources can be found stating that the three dogs were attempting to rape Lady or that Lady became pregnant after her night with Tramp; the latter is impossible because she would have gotten pregnant in the spring, yet she had the puppies shortly before Christmas.
Hey, It's That Sound!: The zoo hyena's laugh done by Dallas McKennon would later become a rather popular stock sound effect, with the "voice" of Ripper Roo from the Crash Bandicoot series being the most well known usage.
Keep Circulating the Tapes: The version that Disney animated in the 1.37:1 Academy ratio, for theaters unable to show widescreen movies, has only received one official home video release, when it was released on VHS and LaserDisc. Reissues of the movie on newer formats only feature the CinemaScope version, leaving the Academy version unable to view, aside from some clips included in some of the bonus features.
Pet Fad Starter: The movie led to a sharp spike in demand for the Cocker Spaniel breed. The poor breeding done to meet the demand compounded the health problems the breed already had.
Screwed by the Lawyers: Peggy Lee sued Disney when the film was released on VHS and LaserDisc, citing that her contract did not allow them to use her voice on video. She eventually collected a seven figure sum, and Disney began including in their contracts rights to "media not yet existing." The same thing happened with the Mexican Spanish dub, as Tramp's voice actor (Roberto Espriu) sued Disney for the same reason, forcing Disney to do another dub with a different cast at Prime Dubb/SDI Media de México.
Talking to Himself: Peggy Lee, Dallas McKennon, Lee Millar and Bill Thompson each perform more than one role in the film.
Trusty was supposed to die after the dogcatcher's wagon hit him, but Walt Disney didn't want another serious death, following the trauma Bambi's mom's demise caused many children.
Boris the Russian Wolfhound (who appears at the pound) was originally supposed to be the male lead of the film, having Tramp's role. However, the title "Lady and Boris"..."just didn't have the right ring to it".
Tramp/Boris was also supposed to have had a song, called "I'm Free as the Breeze", which he sang about his life as a happy stray. It was cut when the film was retooled.
In one early version, the rat spoke and was more of a troublemaker than a genuine menace. He would have had a Jersey gangster sort of personality. His name would also have been Herman.