William "Count" Basie (21 August 1904–26 April 1984) was a jazz pianist, organist, composer, and bandleader.

As a pianist, he had a distinctive and influential style (the song title "Splanky" is an onomatopoetic reference to the sound of his playing), equally at home in the barrelhouse and the concert hall. Willie "The Lion" Smith, James P. Johnson, and Fats Waller were among his influences.

As a bandleader, he created an organization (built upon the remains of Bennie Moten's Kansas City Orchestra) that was a favorite both of dancers and of vocalists such as Frank Sinatra, Ella Fitzgerald, and Sarah Vaughan, and of course Billie Holiday. Equally important, it kept many musicians employed through lean years. Many jazz musicians of note built their chops and earned their bread and butter in Basie's organization.

In addition to Basie, the swinging "All American Rhythm Section" of his orchestra included greats such as Walter Page (bass), Jo Jones (drums), and Freddie Green (guitar). It was the greatest, most swinging rhythm sections in the history of jazz. Chief among its vocalists were, first, Jimmy Rushing and, later, Joe Williams. Over the years it boasted sidemen and soloists like Herschel Evans (tenor sax), Lester Young (tenor sax), Eddie "Lockjaw" Davis (tenor sax), Buddy Tate (tenor sax), Illinois Jacquet (tenor sax), Earle Warren (alto sax), Jack Washington (alto & baritone sax), Harry "Sweets" Edison (trumpet), Buck Clayton (trumpet), Thad Jones (trumpet), Snooky Young (trumpet), Benny Morton (trombone), Benny Powell (trombone), and Dicky Wells (trombone).

Basie also collaborated with artists such as Zoot Sims and Oscar Peterson, and recorded with ensembles large and small, including the Count Basie Trio, the Count Basie Sextet, and the Kansas City Seven. Notable arrangers included Eddie Durham (who helped shape the Basie Orchestra's sound) and Neal Hefti.