The Harmonic (harmɑ́nɪk) is a unique sound produced on the guitar by touching a string very lightly over certain frets with your left hand while your right hand plucks the strings. To allow harmonics to ring you must quickly removing your left hand as you pluck. Producing harmonics on the guitar string requires practice, as the finger pressure and timing must both be accurate.

The term harmonic is sometimes used equivalently with the term overtone, as both sounds are created when the guitar or other instrument produces multiple frequencies known as partials. The primary difference is that harmonics and overtones are counted slightly differently when you are determining where on the string to touch to create the sound you are looking for.