Betamax was a home videocassette tape recording format developed by Sony, released in 1975. The format is generally considered obsolete and hard to find any examples of today.

Sanyo marketed a version as Betacord, but this was also referred to casually as "Beta". In addition to Sony and Sanyo, Beta-format video recorders were also sold by Toshiba, Pioneer, Murphy, Aiwa, and NEC; the Zenith Electronics Corporation and WEGA Corporations contracted with Sony to produce VCRs for their product lines.

Soon after the launch of Betamax, JVC launched a rival format - VHS, which caused a period when there was a battle to see which format consumers would adopt.  Betamax was generally regarded as providing a higher quality image, and had smaller tapes, which made for a lighter video recorder.  However, VHS was cheaper to purchase, could record for longer and could more easily be used to duplicate tapes, meaning that the video rental market saw a preference to use VHS.

Sony began to produce its own VHS recorders in 1988, although went on to produce Betamax until 2002 and even evolved it in Japan into Extended Definition Betamax, with 500+ lines of resolution.