Timex Sinclair was a joint venture established in December 1982 between the British company Sinclair Research and Timex Corporation in an effort to gain an entry into the rapidly growing early-1980s home computer market in North America.

Sinclair Research Ltd was a British consumer electronics company founded by Clive Sinclair in Cambridge. It was originally incorporated in 1973 as Westminster Mail Order Ltd, renamed Sinclair Instrument Ltd, then Science of Cambridge Ltd, then Sinclair Computers Ltd, and finally Sinclair Research Ltd. It remained dormant until 1976, when it was activated with the intention of continuing Sinclair's commercial work from his earlier company Sinclair Radionics, and adopted the name Sinclair Research in 1981.