The sopranino saxophone is the second-smallest type of saxophone. It is tuned to the key of E♭ and sounds one octave higher than the alto saxophone. Adolphe Sax, the inventor of the saxophone, also described a sopranino in the key of F in his patent. This version would sound an octave higher than an F alto (mezzo-soprano) saxophone, but no instruments of this type are known to have been built.

The sopranino saxophone has a soft, sweet sound. It is not commonly used today, but it is still made by companies such as Orsi and Rampone & Cazzani in Italy, Henri Selmer Paris, Yanagisawa in Japan, and Jinbao and Wessex in China. Because of its small size, sopranino saxophones are usually built straight, like a clarinet. However, Orsi also makes curved versions that look like a smaller alto saxophone.

Adolphe Sax originally designed the saxophone family to include sopranino, soprano, alto, tenor, baritone, bass, contrabass, and subcontrabass saxophones in the keys of E♭ and B♭. He also planned versions in the keys of C and F. However, only the soprano, alto, and tenor saxophones were ever made. In the late 1990s, a smaller saxophone called the soprillo was created by the German instrument maker Benedikt Eppelsheim. The soprillo is tuned to B♭ and sounds a fifth higher than the sopranino.

The sopranino saxophone is a transposing instrument, meaning the notes written on the sheet music sound higher when played. It has the same written range as other saxophones, from B♭3 to at least F6. When played, it sounds a minor third higher than the written notes, similar to an E♭ clarinet or soprano cornet. This means the range in concert pitch (the actual sound heard) is from D♭4 to A♭6.

Repertoire

In classical music, the sopranino saxophone is most famously used in the orchestral piece Boléro by French composer Maurice Ravel. Ravel's score calls for a "soprano saxophone in F," but it is likely that no such instrument was ever made. Instead, the part is usually played on an E♭ sopranino or B♭ soprano saxophone.

The sopranino saxophone has been used again in modern music during the 21st century. The American rock band Violent Femmes includes a horn section called "Horns of Dilemma" in their live performances and recordings. This section uses saxophones of many sizes, including the sopranino. Saxophonist Blaise Garza plays the sopranino in the Violent Femmes' 2019 song "I'm Not Gonna Cry."

In addition to classical and rock music, many jazz and improvisation musicians have used the sopranino saxophone. These musicians include Carla Marciano, James Carter, Anthony Braxton, La Monte Young, Roscoe Mitchell, Christophe Monniot, Joseph Jarman, Paul McCandless, Lol Coxhill, Roger Frampton, Hans Koller, Wolfgang Fuchs, Douglas Ewart, Larry Ochs, Vinny Golia, Thomas Chapin, Martin Archer, David Sanborn, Jon Irabagon, Massimo Falascone, Alejandro Arturi, Gianni Gebbia, and Ian Anderson. Ian Anderson is credited with playing the sopranino on Jethro Tull's albums A Passion Play and War Child. The sopranino was also used by the six-member Nuclear Whales Saxophone Orchestra, where Kelley Hart Jenkins played the instrument.