The xylophone is a musical instrument in the percussion family that consists of wooden bars struck by mallets. Each bar is an idiophone tuned to a pitch of a musical scale, whether pentatonic or heptatonic in the case of many African and Asian instruments, diatonic in many western children's instruments, or chromatic for orchestral use.

The term xylophone may be used generally, to include all such instruments such as the marimba, balafon and even the semantron. However, in the orchestra, the term xylophone refers specifically to a chromatic instrument of somewhat higher pitch range and drier timbre than the marimba, and these two instruments should not be confused.