A woodwind instrument is a musical instrument in which sound is produced by blowing against an edge or by a vibrating reed, and in which the pitch is varied by opening or closing holes in the body of the instrument using a mouthpiece.

There are three main sorts of woodwind instrument:

• Single Reed instruments use a reed -- a thinly sliced piece of cane, (or less frequently, plastic)-- that is held against the aperture of the mouthpiece with a ligature. When air is forced between the reed and the mouthpiece, the vibrations create the sound. Single reed instruments include the clarinet and saxophone families of instruments.
• Double Reed instruments use two precisely cut, small pieces of cane joined together at the base . The finished, bound reed is inserted into the top of the instrument and vibrates as air is forced between the two pieces of bound cane. There are two sub-families
  • exposed double reed instruments, where the reed goes between the player's lips. The oboe, cor anglais (also called english horn) and bassoon make up the more popular instruments within this family.
  • capped reed instruments, where there is a cap covering up the reed with a hole in that the player just blows through. This family includes the bagpipes and the crumhorn
• Flute woodwind instruments where the sound is produced by blowing against an edge. There are two subfamilies
  • open flute family, where the player uses their lips to form the stream of air which goes directly from the players lips to the edge, e.g. the transverse flute
  • closed flute family, where the instrument forms and directs the stream over the edge. This family includes whistle and the recorder family

One interesting difference between woodwind and brass instruments is that woodwind instruments are non-directional. This means that the sound produced propagates in all directions with approximately equal volume. Brass instruments, on the other hand, are highly directional, with most of the sound produced travelling straight outward from the bell. This difference makes it significantly more difficult to record a woodwind instrument accurately. It also plays a major role in some performance situations, such as in marching bands.