Channel surfing (also known as channel hopping or zapping) is the practice of quickly scanning through different television channels or radio frequencies to find something interesting to watch or listen to. Modern viewers, who may have cable or satellite services beaming down dozens if not hundreds or thousands of channels, are frequently channel surfing. It is common for people to scan channels when commercial broadcasters switch from a show over to running commercials.

The term is most commonly associated with television, where the practice became common with the wide availability of the remote control. The first published use of the term is November 1986, in an article by The Wall Street Journal.

Viewers' propensity to channel surf was apparently a factor leading toward the current ATSC standard for terrestrial television, digital television in North America. An ATSC signal can be locked onto and start being decoded within about one second, while it can take several seconds to begin decoding a Digital Video Broadcasting (DVB) signal.