The videotape format war was a period of competition or "format war" of incompatible models of consumer-level analog video videocassette and video cassette recorders (VCR) in the late 1970s and the 1980s, mainly involving the Betamax and Video Home System (VHS) formats. VHS ultimately emerged as the preeminent format.

A format war is a competition between similar but mutually incompatible technical standards that compete for the same market, such as for data storage devices and recording formats for electronic media. It is often characterized by political and financial influence on content publishers by the developers of the technologies. Developing companies may be characterized as engaging in a format war if they actively oppose or avoid interoperable open-industry technical standards in favor of their own.