The Xbox is a home video game console manufactured by Microsoft that is the first installment in the Xbox series of video game consoles. It was released as Microsoft's first foray into the gaming console market on November 15, 2001, in North America, followed by Australia, Europe and Japan in 2002. It is classified as a sixth-generation console, competing with Sony's PlayStation 2, Sega's Dreamcast and Nintendo's GameCube. It was also the first major console produced by an American company since the release of the Atari Jaguar in 1993.

The console was announced in March 2000. With the release of the PlayStation 2, which featured the ability to playback CD-ROMs and DVDs in addition to playing games, Microsoft became concerned that game consoles would threaten the personal computer as an entertainment device for living rooms. Whereas most games consoles to that point were built from custom hardware components, the Xbox was built around standard personal computer components, using variations of Microsoft Windows and DirectX as its operating system to support games and media playback, and featuring a 733 MHz Intel Pentium III CPU and a 233 MHz Nvidia GeForce 3-based NV2A GPU, the latter two making the Xbox technically more powerful compared to its rivals. The Xbox was the first console to feature a built-in hard disk. The console also was built with direct support for broadband connectivity to the Internet via an integrated Ethernet port, and with the release of Xbox Live, a fee-based online gaming service, a year after the console's launch, Microsoft gained an early foothold in online gaming and made the Xbox a strong competitor in the sixth generation of consoles. The popularity of killer app blockbuster titles such as Bungie's Halo 2 contributed to the popularity of online console gaming, and in particular first-person shooters.

The Xbox had a record-breaking launch in North America, selling 1.5 million units before the end of 2001, aided by the popularity of one of the system's launch titles, Halo: Combat Evolved, which sold a million units by April 2002. The system went on to sell a worldwide total of 24 million units, including 16 million in North America; however, Microsoft was unable to make a steady profit off the console, which had a manufacturing price far more expensive than its retail price, despite its popularity, losing over $4 billion during its market life. The system outsold the GameCube and the Sega Dreamcast, but was vastly outsold by the PlayStation 2, which had sold over 155 million units by the system's end of production. It also underperformed outside of the Western market; particularly, it sold poorly in Japan due to its large console size and an overabundance of games marketed towards American audiences instead of Japanese-developed titles. Production of the system was discontinued starting in 2005. The Xbox was the first in an ongoing brand of video game consoles developed by Microsoft, with a successor, the Xbox 360, launching in November 2005, followed by the Xbox One in 2013 and the Xbox Series X and Series S consoles in 2020.