In popular music, a guitar solo is a melodic passage, section, or entire piece of music written for an electric guitar or an acoustic guitar. Guitar solos, which often contain varying degrees of improvisation, are used in many styles of popular music such as blues, jazz, rock and metal styles such as swing and jazz fusion. Guitar solos are also used in classical music forms such as chamber music and concertos.^{[citation needed]}

Guitar solos range from unaccompanied works for a single guitar to compositions with accompaniment from other instruments. The accompaniment musicians for a guitar solo can range from a small ensemble such as a jazz quartet or a rock band, to a large ensemble such as an orchestra or big band. Unaccompanied acoustic guitar music is found in folk and classical music dating as far back as the instrument has existed, and the use of an acoustic guitar as a solo voice within an ensemble dates back at least to the Baroque concerto.

Even though guitar solos are used in a wide range of genres, the term guitar solo often refers specifically to the rock music genre. The dramatic, amplified electric guitar solo has become a characteristic part of rock music. Since the 1960s, electric guitarists have often altered the timbre of their guitar adding electronic guitar effects such as reverb, distortion, delay, and chorus to make the sound fuller and add harmonic overtones.