The Atari 8-bit family is a series of 8-bit home computers introduced by Atari, Inc. in 1979 as the Atari 400 and Atari 800 and manufactured until 1992. All of the machines in the family are technically similar and differ primarily in packaging. They are based on the MOS Technology 6502 CPU running at 1.79 MHz, and were the first home computers designed with custom coprocessor chips. This architecture enabled graphics and sound capabilities more advanced than contemporary machines, and gaming on the platform was a major draw. The first-person space combat simulator Star Raiders is considered the platform's killer app. The systems launched with a series of plug and play peripherals that used the Atari SIO serial bus system, an early analog of USB.

To meet stringent FCC requirements, much of the circuitry of the original machines is enclosed in a cast aluminum block, which made them physically robust but expensive to produce. The 400 and 800 were replaced by the XL series in 1983, then–after the company was sold and reestablished as Atari Corporation–the XE models in 1985. The XL and XE are lighter in construction while having Atari BASIC built-in and reducing the number of joystick ports from 4 to 2. The 130XE increased the memory to 128K of bank-switched RAM.

The Atari 8-bit computer line sold two million units during its major production run between late 1979 and mid-1985. They were not only sold through dedicated computer retailers, but department stores such as Sears, using an in-store demo to attract customers. The primary competition in the worldwide market came when the Commodore 64, with similar graphics performance, was introduced in 1982.