The sarrusophone is a transposing musical instrument invented by Pierre-Louis Gautrot in 1856 to compete with the saxophone as a replacement for the bassoon in bands. It was so similar to the saxophone that Adolphe Sax repeatedly filed lawsuits against Sarrus. It was named after the French bandmaster Pierre Auguste Sarrus (1813-1876).

It is made of metal, resembles an ophecleide in shape, and is played with a double-reed. Its fingering is similar to a saxophone, and it was made in sizes from sopranino to subcontrabass.

The sarrusophone is rarely called for in classical music. However, around the turn of the 20th century, the contrabass sarrusophone in E-flat enjoyed a vogue as a less physically fragile subsitute for the contrabassoon, so that it is called for in, for example, Maurice Ravel's L'heure espagnol (1907) and Arrigo Boito's Nerone (1924). These parts are nowadays often played on the contrabassoon.

A very unusual example of the sarrusophone in jazz is on the 1924 recording by Clarence Williams Blue 5 of "Mandy, Make Up Your Mind", with the sarrusophone played by Sidney Bechet.

The sarrusophone is now obsolete and only used as a novelty upon occasions. It had poor intonation and a sound less clear than that of the saxophone.