Truman Eliot "Jack" Jenney (May 12, 1910 – December 16, 1945) was a jazz trombonist.
Born in Mason City, Iowa, Jenney first played trumpet, then switched to trombone. His father was a musician and music teacher. Jenney performed in his father's band from age 11, but his professional work began with Austin Wylie in 1928. He would go on to work with Isham Jones, Red Norvo, Artie Shaw, Mal Hallett, and Waring's Pennsylvanians, and appear in the film Syncopation. He has been called "the greatest trombonist of the Big Band era" and won the DownBeat Reader's Poll for trombone in 1940.
He led his own band for a year in 1938–39, but it was a financial failure. He was drafted into the United States Navy in 1943, but also played as a studio musician the following year. He died on December 16, 1945, in Los Angeles, California, from complications following an appendectomy.