David Roy Eldridge (January 30, 1911 – February 26, 1989), nicknamed "Little Jazz", was an American jazz trumpeter. His sophisticated use of harmony, including the use of tritone substitutions, his virtuosic solos exhibiting a departure from the dominant style of jazz trumpet innovator Louis Armstrong, and his strong impact on Dizzy Gillespie mark him as one of the most influential musicians of the swing era and a precursor of bebop.

Eldridge was born on the North Side of Pittsburgh, Pennsylvania, on January 30, 1911, to parents Alexander, a wagon teamster, and Blanche, a gifted pianist with a talent for reproducing music by ear, a trait that Eldridge claimed to have inherited from her. Eldridge began playing the piano at the age of five; he claimed to have been able to play coherent blues licks at even this young age. The young Eldridge looked up to his older brother, Joe Eldridge (born Joseph Eldridge, 1908, North Side of Pittsburgh, Pennsylvania, died March 5, 1952), particularly because of Joe's diverse musical talents on the violin, alto saxophone, and clarinet. Roy took up the drums at the age of six, taking lessons and playing locally. Joe recognized his brother's natural talent on the bugle, which Roy played in a local church band, and tried to convince Roy to play the valved trumpet. When Roy began to play drums in his brother's band, Joe soon convinced him to pick up the trumpet, but Roy made little effort to gain proficiency on the instrument at first. It was not until the death of their mother, when Roy was eleven, and his father's subsequent remarriage that Roy began practicing more rigorously, locking himself in his room for hours, and particularly honing the instrument's upper register. From an early age, Roy lacked proficiency at sight-reading, a gap in his musical education that would affect him for much of his early career, but he could replicate melodies by ear very effectively.

Eldridge led and played in a number of bands during his early years, moving extensively throughout the American Midwest. He absorbed the influence of saxophonists Benny Carter and Coleman Hawkins, setting himself the task of learning Hawkins's 1926 solo on "The Stampede" (by Fletcher Henderson's Orchestra) in developing an equivalent trumpet style.

Eldridge left home after being expelled from high school in ninth grade, joining a traveling show at the age of sixteen; the show soon folded, however, and he was left in Youngstown, Ohio. He was then picked up by the "Greater Sheesley Carnival," but returned to Pittsburgh after witnessing acts of racism in Cumberland, Maryland that significantly disturbed him. Eldridge soon found work leading a small band in the traveling "Rock Dinah" show, his performance therein leading swing-era bandleader Count Basie to recall young Roy Eldridge as "the greatest trumpet I'd ever heard in my life." Eldridge continued playing with similar traveling groups until returning home to Pittsburgh at the age of 17.

At the age of 20, Eldridge led a band in Pittsburgh, billed as "Roy Elliott and his Palais Royal Orchestra", the agent intentionally changing Eldridge's name because "he thought it more classy." Roy left this position to try out for the orchestra of Horace Henderson, younger brother of famed New York City bandleader Fletcher Henderson, and joined the ensemble, generally referred to as The Fletcher Henderson Stompers, Under the Direction of Horace Henderson. Eldridge then played with a number of other territory bands, staying for a short while in Detroit before joining Speed Webb's band which, having garnered a degree of movie publicity, began a tour of the Midwest. Many of the members of Webb's band, annoyed by the leader's lack of dedication, left to form a practically identical group with Eldridge as bandleader. The ensemble was short-lived, and Eldridge soon moved to Milwaukee, where he took part in a celebrated cutting contest with trumpet player Cladys "Jabbo" Smith, with whom he later became good friends.

Eldridge moved to New York in November 1930, playing in various bands in the early 1930s, including a number of Harlem dance bands with Cecil Scott, Elmer Snowden, Charlie Johnson, and Teddy Hill. It was during this time that Eldridge received his nickname, 'Little Jazz', from Ellington saxophonist Otto Hardwick, who was amused by the incongruity between Eldridge's raucous playing and his short stature. At this time, Eldridge was also making records and radio broadcasts under his own name. He laid down his first recorded solos with Teddy Hill in 1935, which gained almost immediate popularity. For a brief time, he also led his own band at the reputed Famous Door nightclub. Eldridge recorded a number of small group sides with singer Billie Holiday in July 1935, including "What a Little Moonlight Can Do" and "Miss Brown to You", employing a Dixieland-influenced improvisation style. In October 1935, Eldridge joined Fletcher Henderson's Orchestra, playing lead trumpet and occasionally singing. Until he left the group in early September 1936, Eldridge was Henderson's featured soloist, his talent highlighted by such numbers as "Christopher Columbus" and "Blue Lou." His rhythmic power to swing a band was a dynamic trademark of the jazz of the time. It has been said that "from the mid-Thirties onwards, he had superseded Louis Armstrong as the exemplar of modern 'hot' trumpet playing".

In the fall of 1936, Eldridge moved to Chicago to form an octet with older brother Joe Eldridge playing saxophone and arranging. The ensemble boasted nightly broadcasts and made recordings that featured his extended solos, including "After You've Gone" and "Wabash Stomp." Eldridge, fed up with the racism he had encountered in the music industry, quit playing in 1938 to study radio engineering. He was back to playing in 1939, when he formed a ten-piece band that gained a residency at New York's Arcadia Ballroom.

In April 1941, after receiving many offers from white swing bands, Eldridge joined Gene Krupa's Orchestra, and was successfully featured with rookie singer Anita O'Day. In accepting this position, Eldridge became one of the first black musicians to become a permanent member of a white big band. Eldridge was critical in changing the course of Krupa's big band from pop-oriented "schmaltz" to jazz. The group's cover of Jimmy Dorsey's "Green Eyes," previously an entirely orchestral work, was transformed into jazz via Eldridge's playing; critic Dave Oliphant notes that Eldridge "lift[ed]" the tune "to a higher level of intensity." Eldridge and O'Day were featured in a number of recordings, including the novelty hit "Let Me Off Uptown" and "Knock Me a Kiss".