The tenor saxophone is a medium-sized member of the saxophone family, a group of instruments invented by Adolphe Sax in the 1840s. The tenor and the alto are the two most commonly used saxophones. The tenor is pitched in the key of B♭ (while the alto is pitched in the key of E♭), and written as a transposing instrument in the treble clef, sounding an octave and a major second lower than the written pitch. Modern tenor saxophones which have a high F♯ key have a range from A♭2 to E5 (concert) and are therefore pitched one octave below the soprano saxophone. People who play the tenor saxophone are known as "tenor saxophonists", "tenor sax players", or "saxophonists".

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.