Polyphony is a type of musical texture consisting of two or more simultaneous lines of independent melody, as opposed to a musical texture with just one voice (monophony) . Each of these melodies is essentially equal in importance, and they can be thought of as melodies in their own right, one that could be sung, played, or listened to independently of the others. But it is the combination of the different strands, all interacting together, that creates polyphony. Polyphony may be likened to a dialogue, a discussion, or even an argument between two or more speakers, all talking concurrently. As a result, polyphony may be judged as the most complex of all the musical textures, since it challenges a listener to concentrate on several, equally important layers of sound.

Polyphony is not limited to Western music, and traditional (non-professional) polyphony has a wide, if uneven, distribution among the peoples of the world. Most polyphonic regions of the world are in sub-Saharan Africa, Europe, and Oceania. The term polyphony is also sometimes used more broadly to describe any musical texture that is not monophonic. Such a perspective considers homophony as a sub-type of polyphony.

Polyphony is an important concept in music technology, as it refers to the maximum number of notes that a keyboard or sound module can produce at one time.