The soprano saxophone is a higher-register variety of the saxophone, a woodwind instrument, invented in the 1840s. The soprano is the third smallest member of the saxophone family, which consists (from smallest to largest) of the soprillo, sopranino, soprano, alto, tenor, baritone, bass, contrabass saxophone and tubax. Soprano saxophones are the smallest saxophone in common use.
A transposing instrument pitched in the key of B♭, modern soprano saxophones with a high F♯ key have a range from B♭3 to F♯6 and are therefore pitched one octave above the tenor saxophone. Some saxophones have additional keys, allowing them to play an additional F♯ and G at the top of the range. These extra keys are commonly found on more modern saxophones. Additionally, skilled players can make use of the altissimo register, which allows them to play even higher. There is also a soprano pitched in C, which is less common and until recently had not been made since around 1940.
The soprano saxophone can be compared to the B♭ clarinet, although the clarinet can play an augmented fourth lower and over a fifth higher. Due to the smaller bore of the soprano, it is less forgiving with respect to intonation, though an experienced player will use alternate fingerings or vary breath support, tongue position or embouchure to compensate. Professional players will use the technique of voicing to fix problems with intonation. Due to its similarity in tone to the oboe, the soprano saxophone is sometimes used as a substitute for it.