The ZX Spectrum is an 8-bit home computer developed and marketed by Sinclair Research. The Spectrum played a pivotal role in the history of personal computers and video games, especially in the United Kingdom. It was one of the all-time bestselling British computers with over five million units sold. It was first released in Britain on 23 April 1982 with releases in some other regions, including West Germany and the United States, after that year.

The machine was designed by the English entrepreneur and inventor Sir Clive Sinclair and his small team in Cambridge, and was manufactured in Dundee, Scotland by Timex Corporation. It was made to be small, simple, and most importantly inexpensive, with as few components as possible. The addendum "Spectrum" was chosen to highlight the machine's colour display, which differed from the black-and-white display of its predecessor, the ZX81. Rick Dickinson designed its distinctive case, rainbow motif, and rubber keyboard. Video output is transmitted to a television set rather than a dedicated monitor, while application software is loaded and saved onto compact audio cassettes.

The ZX Spectrum was initially distributed by mail order, but after severe backlogs it was sold through High Street chains in the United Kingdom. It was released in the US as the Timex Sinclair 2068 in 1983, and in some parts of Europe as the Timex Computer 2048. There are seven models overall, ranging from the entry level with 16 KB RAM released in 1982 to the ZX Spectrum +3 with 128 KB RAM and built-in floppy disk drive in 1987. The machine primarily competed with the Commodore 64, BBC Micro, Dragon 32, and the Amstrad CPC range. Over 24,000 software products were released for the ZX Spectrum.

Its introduction led to a boom in companies producing software and hardware, the effects of which are still seen. It was among the first home computers aimed at a mainstream UK audience, with some crediting it for launching the British information technology industry. The Spectrum was Britain's top-selling computer until the Amstrad PCW surpassed it in the 1990s. It was discontinued in 1992.