Delay (dəlé) is an audio effect used by guitarists, which repeats a note electronically after the original is played. There are commonly three adjustable parameters that the guitarist can set for the desired delay effect: number of times the note is repeated, the volume of the repeated note, and the length of time between repeated notes (usually in milliseconds).

A delay effect can either be produced by pedals or rack-mounted effects, and can be used in varied applications, such as the generation of “fill” notes or to mimic the “water tank” reverb sound found on many rockabilly recordings.