Xbox is a video gaming brand created and owned by Microsoft. The brand consists of five video game consoles, as well as applications (games), streaming services, an online service by the name of Xbox network, and the development arm by the name of Xbox Game Studios. The brand was first introduced in the United States in November 2001, with the launch of the original Xbox console.

The original device was the first video game console offered by an American company after the Atari Jaguar stopped sales in 1996. It reached over 24 million units sold by May 2006. Microsoft’s second console, the Xbox 360, was released in 2005 and has sold 86 million units as of October 2021. The third console, the Xbox One, was released in November 2013 and has sold 51 million units. The fourth line of Xbox consoles, the Xbox Series X and Series S, was released in November 2020. The head of Xbox is Phil Spencer, who succeeded former head Marc Whitten in late March 2014.

The fourth generation of Xbox models, simply named Xbox, includes the Xbox Series X and Xbox Series S that launched on November 10, 2020. Both are considered members of the ninth generation of video game consoles alongside the PlayStation 5, also released that month.

The Xbox Series X and Series S are high- and low-end versions comparable to the Xbox One X and Xbox One S models, respectively, with all games designed for this model family playable on both systems. The Xbox Series X is estimated to be four times as powerful as Xbox One X, with support for 8K resolution and up to 120 frames-per-second rendering, with a nominal target of 4K resolution at 60 frames per second. The Xbox Series S is a digital-only unit with less graphic processing power, but can still render at a nominal 1440p resolution at 60 frames per second with support for 4K upscaling. Both consoles feature support for new graphics rendering systems including real-time ray-tracing, and the new Xbox Velocity Architecture that works with the internal SSD drive to maximize the rate of texture streaming to the graphics processor, among other features. Besides games for this new console family, both consoles are fully compatible with all Xbox One games and most hardware, as well as all backward compatible games that were playable on the Xbox One from the Xbox 360 and original Xbox console.

To help transition consumers, Microsoft introduced its Smart Delivery system which most of its first-party games and several third-party games will use to offer free updates to Xbox One versions of games to the Xbox Series X/S version over the first few years of the consoles’ launch.