Arthur Edward Pepper Jr. was an American jazz musician, most known as an alto saxophonist. He occasionally performed and recorded on tenor saxophone, clarinet and bass clarinet. Active primarily in West Coast jazz, Pepper first came to prominence in Stan Kenton's big band. He was known for his emotionally charged performances and several stylistic shifts throughout his career, and was described by critic Scott Yanow as having "attained his goal of becoming the world's greatest altoist" at the time of his death in 1982.

The alto saxophone is a member of the saxophone family of woodwind instruments. Saxophones were invented by Belgian instrument designer Adolphe Sax in the 1840s and patented in 1846. The alto saxophone is pitched in the key of E♭, smaller than the B♭ tenor but larger than the B♭ soprano. It is the most common saxophone and is used in popular music, concert bands, chamber music, solo repertoire, military bands, marching bands, pep bands, carnatic music, and jazz.