AtariWriter is a word processor program for the Atari 8-bit computers released by Atari, Inc. as a 16 kB ROM cartridge in 1983. The program was fast and easy to use, while still having enough features to allow the creation of complex documents. It was a success for the platform, with at least 800,000 units initially sold, not including international versions and later updates. It was among the company's most successful software products.

Atari introduced Atari Word Processor, its first branded word processor, in 1981. Reviews unanimously praised its features but also noted its usability problems, including its difficulty and demanding system requirements. When the new models of the XL series were introduced, Word Processor was abandoned in favour of a simpler program that would run on any machine. William Robinson, author of Datasoft's Text Wizard, was hired for the new software project, with him modifying the program to run from a cartridge.

Positive reviews followed its release, with concerns also raised about the lack of mail merge and a spell checker, and the absence of printer drivers for any printers other than Atari's. To meet the demand for non-Atari printers, at least 25,000 copies of an add-on printer pack were sold through direct sales and the Atari Program Exchange. In 1986, Atari released the AtariWriter Plus, with new features along with a spell checker and mail merge available on floppy disk. AtariWriter 80, the final version of the software released in 1989, added support for the XEP80 80-column display. AtariWriter also spawned a port to the Atari ST with the ST Writer program, which was offered free on early models of the ST.

Atari's original marketing plan for the 8-bit family of machines, which includes the Atari 400 and 800, was to market the 400 to the education and games sector, and the 800 to small-office settings where CP/M and the Apple II were successful. Unfortunately, the lack of useful business software hindered any sales to the office market, and the machine quickly garnered a reputation as a glorified games box.

In 1980, Atari addressed this problem by introducing their own Atari Word Processor. It shipped on a copy protected floppy disk and required 48 kB of RAM. These requirements meant that the user had to have, at a minimum, a fully-expanded 800 and at least one Atari 810 disk drive. The machines lacked a parallel port and Atari did not sell printers with the SIO adaptor built-in, so printing required the Atari 850 interface and a parallel printer like the Atari 825 (a white labelled Centronics 737) or the widely recommended Epson MX-80.

While the software program was feature-packed, including support for things like two-column layout and super- and sub-scripting, reviewers pointed out that it was difficult to use. In addition to an extensive set of editing commands using control keys, including cursor commands that did not use the system's own cursor keys, more complex operations like loading documents or printing required trips through multi-level text menus. As these were essentially impossible to remember, a quick-reference sheet was included and the documentation was designed to stand up on a desk for continual use.

Word Processor was one of three major word processing software programs in the early days of the platform, with reviews from 1982 generally comparing it to Text Wizard from Datasoft and Letter Perfect from LKJ. These programs were much simpler than AtariWriter in terms of features, but they could run on any machine in the lineup and were far easier to use. For all of these reasons, they easily outsold Atari Word Processor. Text Wizard was often considered the best-buy, and Letter Perfect the best overall; Atari's was never recommended.

Sometime in late 1981, Gary Furr left his job at GTE where he wrote application software specifications for government contractors. Moving to Atari, Furr and product manager Peggy Allen soon began planning to replace Word Processor. Instead of modifying the software, they decided to abandon it entirely. Furr used Word Processor to write the design specification for AtariWriter in March or April 1982.