The octavin (also spelled oktavin)[1] is a 19th century woodwind instrument with a conical bore and a single reed.

However, the octavin differs in three respects: first, its conical bore has a smaller taper than that of a saxophone; second, its body is made of wood, rather than metal; third, its usual shape is more similar to that of a bassoon, having two parallel straight sections joined at the bottom, with the mouthpiece attached to the top of one section and a metal bell to the top of the other.

A few straight octavins exist, having a wooden bell; in this configuration it resembles a tarogato but has a smaller taper.

[5] The octavin was a commercial failure and is now extremely rare, being considered a curiosity by collectors.

[7] Repertoire for the instrument is scarce: one of the only pieces for the octavin is a sonatina composed by Jeff Britting (b.