A volume swell is a musical crescendo commonly associated with the electric guitar. Roughly speaking the sound of a guitar note is characterised by an initial 'attack' where the pick or nail produces higher pitched overtones over the top of the fundamental note, followed by a diminution of these overtones. Consequently the tail end of the note is softer than the attack.

Volume swells (also known by guitarists as "violining" because of the smooth and sustaining sound it can produce) alter the tone of the note, reducing the trebly tone of the attack and allowing the softer tone that follows to sustain.

The technique is often executed by the little finger of the guitarist which is wrapped around the volume pot of their guitar. When the note is struck the volume is increased from zero by a rolling motion of the little finger. The sound is emotive and particularly enhanced by delay effects and distortion.

Jan Akkerman from the band Focus has been credited with the discovery of the technique but particularly masterful examples of its use can also be found in the album Exit Stage Left by the Canadian rock band Rush and in the works of Norwegian guitarist Terje Rypdal.