A percussion instrument produces sound when it is struck, shaken, or scraped. The category includes drums of all kinds, cymbals, xylophones, triangles, tambourines, and hundreds of other instruments from cultures around the world.

Some percussion instruments have definite pitch; others produce indefinite noise-like sounds. In the orchestra the percussion section provides rhythm, color, and dramatic accents. In many popular and traditional ensembles percussion is the primary rhythmic foundation.

Technique varies widely. Some instruments are played with sticks or mallets of different hardness; others with the hands. The same instrument can yield many timbres depending on where and how it is struck. Percussionists often play several instruments in the course of a single piece, requiring quick changes and careful organization.

The sheer variety of percussion makes it one of the most colorful sections of any ensemble.