Google Chrome OS is a Linux-based operating system designed by Google to work exclusively with web applications. Google announced the operating system on July 7, 2009 and made it an open source project, called Chromium OS, that November.

Unlike Chromium OS, which can be compiled from the downloaded source code, Chrome OS only ships on specific hardware from Google's manufacturing partners. The user interface takes a minimalist approach, resembling that of the Google Chrome web browser. Since Google Chrome OS is aimed at users who spend most of their computer time on the Web, the only application on the device is a browser incorporating a media player and a file manager.

The launch date for retail hardware featuring Chrome OS slipped after Google first announced the operating system: from an initial forecast date in late 2010 to June 15, 2011, when "Chromebooks" from Samsung (and then Acer in July) actually shipped.

Google developers began coding the operating system in 2009, inspired by the growing popularity and lower power consumption of netbooks and the focus of these small laptops on Internet access. To ascertain marketing requirements for an operating system focused on netbook Web transactions, the company did not do the usual demographic research generally associated with a large software development project. Instead, engineers relied on more informal metrics, including monitoring the usage patterns of some 200 Chrome OS machines used by Google employees. Developers also noted their own usage patterns. Matthew Papakipos, former engineering director for the Chrome OS project, put three machines in his house and found himself logging in for brief sessions: to make a single search query or send a short email.

Google Chrome is a freeware web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows on September 2, 2008, and the public stable release was on December 11, 2008. As of May 2012^[update], Google Chrome has approximately 33% worldwide usage share of web browsers, making it the most widely used web browser, according to Statcounter.

In September 2008, Google released a large portion of Chrome's source code as an open source project called Chromium.

For six years, Google's Chief Executive Eric Schmidt opposed the development of an independent web browser. He stated that "At the time, Google was a small company", and he did not want to go through "bruising browser wars". However, after co-founders Sergey Brin and Larry Page hired several Mozilla Firefox developers and built a demonstration of Chrome, Schmidt admitted that "It was so good that it essentially forced me to change my mind".

The release announcement was originally scheduled for September 3, 2008, and a comic by Scott McCloud was to be sent to journalists and bloggers explaining the features within the new browser. Copies intended for Europe were shipped early and German blogger Philipp Lenssen of Google Blogoscoped made a scanned copy of the 38-page comic available on his website after receiving it on September 1, 2008. Google subsequently made the comic available on Google Books and mentioned it on their official blog along with an explanation for the early release.