GalliumOS was a Linux distribution for ChromeOS devices, developed by the community-supported GalliumOS project. The distribution was made for Chrome hardware including Chromebook, Chromebox, Chromebit and Chromebase. GalliumOS beta1 was released on 10 November 2015.

GalliumOS was based on Xubuntu and maintained compatibility with the Ubuntu repositories.^[1] Multiple sources indicate that Galliums' boot time was faster than other Linux distributions made for ChromeOS. It was optimized to limit stalls and had integrated touchpad drivers.^[2][3]

GalliumOS was compatible with some ChromeOS devices. It was necessary to prepare the device in different ways based on the hardware chipset.

As of 2022, the GalliumOS project has been discontinued. Their wiki advises existing GalliumOS users to migrate to another Linux OS due to security hazards.

As of 2023, contributors of Chrultrabook project have upstreamed support for ChromeOS devices - meaning that any non-LTS Linux distribution will work. For more information, visit project's documentation page.

Some Chromebooks require a third-party firmware update before they can boot other operating systems, including GalliumOS. Chromebook firmware can be updated after disabling hardware write-protect, a process that varies by model. A firmware installer script is available for most models, written by MrChromebox.