Media spin-off is the process of deriving new radio or television programs from existing ones (see list of television spin-offs). Spin-offs work with varying degrees of success. Some become very popular and last for a number of seasons, whereas others exceed the popularity of the forebearing show and others are poorly received and have considerably shorter life spans.

This phenomenon was already established in radio before the advent of commercial broadcast television, for example The Great Gildersleeve was a spin-off from Fibber McGee and Molly. The Great Guildersleeve might even have been the very first spin-off, when the popular character from Fibber McGee and Molly was given his own show.

Jack Benny's popular radio program spawned at least two spin-offs when blustery bandleader Phil Harris and naif Dennis Day launched their own programs after their success on Benny's show.

In genre fiction, the term parallels the usage in television; it is usually meant to indicate a substantial change in narrative viewpoint and activity from that (previous) storyline based around the activities of the series' principal protagonist(s) and so is a shift to that action and overall narrative thread of some other protagonist(s), which now becomes the central or main thread (storyline) of the new sub-series. The new protagonist generally appears first as a minor or supporting character in the main story line within a given milieu, and it is very common for the previous protagonist to have a supporting or cameo role, at the least as a historical mention, in the new sub-series.