MSX was the name of a standardized home computer architecture in the 1980s. It was a Microsoft-led attempt to create unified standards among hardware makers, conceived by one-time Microsoft Japan executive Kazuhiko Nishi. Despite Microsoft's involvement, MSX-based machines were seldom seen in the United States but were hugely popular in other markets . Eventually 5 million MSX-based units were sold world-wide.

Nishi proposed MSX as an attempt to create a single industry standard for home computers. Inspired by the success of VHS as a standard for video cassette recorders, many Japanese electronic manufacturers along with Goldstar, Philips and Spectravideo built and promoted MSX computers. Any piece of hardware or software with the MSX logo on it was compatible with MSX products of other manufacturers. In particular, the expansion cartridge form and function were part of the standard; any MSX expansion or game cartridge would work in any MSX computer.

Nishi's standard consisted primarily of several off-the-shelf parts; the main CPU was a 3.58 MHz Zilog Z80, the graphics chip a Texas Instruments TMS9918 with 16 KB (KiB) of dedicated VRAM, the sound was provided by the AY-3-8910 chip manufactured by General Instrument (GI), and an Intel 8255 Programmable Peripheral Interface chip was used for the parallel I/O such as the keyboard (and partly by the I/O ports provided by the AY-3-8910). This was a choice of components that was shared by many other home computers and games consoles of the period, such as the ColecoVision home computer (an emulator was later available with which MSX systems could run some of its software), and the Sega SG-1000 video game system. Most MSX systems soon starting to integrate not only the common "glue logic" components but also the Z80 CPU, the sound chip, the 8255 PIO and the Video Display Processor into a single chip, called an MSX-Engine chip. The result was that one only needed an MSX-Engine chip and some ROM and RAM chips to build a basic system, which greatly reduced production costs. However, almost all MSX systems used a professional keyboard, not a chiclet keyboard, which drove the price up again. So these components alongside Microsoft's MSX BASIC made the MSX a competitive, though somewhat expensive, home computer package.

The system MSX most closely resembled was the Spectravideo SV-328 home computer (Spectravideo even claimed to be "MSX compatible" in advertisements before the actual launch of MSX systems) but it was in fact not completely compatible with it. This led to a new and short-lived kind of software cracking: converting. Since the MSX games were unplayable on the SV-328 computer, SV-328 crackers developed a method of modifying the (MSX) games to make them work on the SV-328. In most cases this included downloading the MSX BIOS to the SV-328 from tape or floppy disk. Spectravideo later launched a system, the SV-728, which did completely adhere to the MSX standard.

Before the appearance and great success of the Nintendo Famicom, MSX was the platform for which major Japanese game studios, such as Konami and Hudson Soft, produced their titles. The Metal Gear series was originally written for MSX hardware.