A rerun or repeat is a re-airing of an episode of a media (usually television) program. The invention of the rerun is generally credited to Desi Arnaz. Some viewers find reruns annoying, although many viewers appreciate the opportunity to re-watch a programme they enjoyed or watch one they missed the first time round. There are two types of reruns, those that occur during a hiatus, and those that occur when a program is syndicated.

In the UK, the word "Repeat" refers only to a single episode; "rerun" or "rerunning" is the preferred term for an entire series/season. It is also used for programs shown less than a week after the original broadcast, before the next episode of the series.