A percussion instrument, similar to the marimba, that consists of a row of tuned wooden keys or bars, mounted on a horizontal rack, graduated in length to sound a chromatic scale. Concert xylophones also have tube resonators below the bars to enhance the tone and sustain.

Arranged horizontally in the manner of a piano keyboard, and usually struck with mallets of varying sizes, the xylophone produces a sharp and penetrating tone. In general terms, the xylophone is a soprano or high register marimba (the difference being in the tuning and timbre).

Although it developed into its modern form in Europe during the 20th century, the xylophone is descended from many similar types of African and Asian instruments dating back at least to the 14th century. Xylophones were introduced to European orchestral music in the late 19th century, in such works as Saint -Saens' 'Dance Macabre' (1874). A myriad of works for other instruments have been transcribed for xylophones, from J.S. Bach's 'Two Part Inventions' to popular music now in orchestral and jazz ensembles throughout the west.

Xylophones continue to have traditional significance throughout much of Africa, Malaysia, Melanesia, Indonesia and regions of the Americas. Some large xylophones require 2 or 3 performers using up to 6 mallets to strike the keys.