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.

Woodwind instruments are a family of musical instruments within the greater category of wind instruments. Common examples include flute, clarinet, oboe, bassoon, and saxophone. There are two main types of woodwind instruments: flutes and reed instruments. The main distinction between these instruments and other wind instruments is the way in which they produce sound. All woodwinds produce sound by splitting the air blown into them on a sharp edge, such as a reed or a fipple. Despite the name, a woodwind may be made of any material, not just wood. Common examples of other materials include brass, silver, cane, and other metals such as gold and platinum. The saxophone, for example, though made of brass, is considered a woodwind because it requires a reed to produce sound. Occasionally, woodwinds are made of earthen materials, especially ocarinas.