Jack K. Pleis (May 11, 1917 – December 5, 1990) was an American jazz pianist, arranger, conductor, composer and producer. He recorded on London and Decca Records in the 1950s, and Columbia Records in the 1960s. During the course of his career, Pleis worked with many artists, including Louis Armstrong, Harry Belafonte, Bing Crosby, Sammy Davis Jr., Benny Goodman, Earl Grant, Brenda Lee, and Joe Williams. Between 1950 and 1976, over 150 songs were arranged by Pleis.