The film score for was composed and conducted by Oliver Wallace. Recording artist Peggy Lee wrote the songs with Sonny Burke and assisted with the score as well.[5] In the film, she sings: "He's a Tramp", "La La Lu", "The Siamese Cat Song" and "What Is a Baby?".[36] She helped promote the film on the Disney TV series, explaining her work with the score and singing a few of the film's numbers.[5] These appearances are available as part of the Lady and the Tramp Platinum Edition DVD set.

On 16 November 1988, Peggy Lee sued the Walt Disney Company for breach of contract, claiming that she retained the rights to transcriptions of the music, arguing that videotape editions were transcriptions.[37] After a protracted legal battle, she was awarded $2.3 million in 1991.[38]

The remastered soundtrack of Lady and the Tramp was released on CD by Walt Disney Records on September 9, 1997 and was released as a digital download on September 26, 2006