XOS or Xos may refer to:
- XOS (operating system), an Android-based operating system
- XOS 3.0, 4.0, and 5.0, Red Hat Enterprise Linux derivatives
- XOS valuation, a kind of utility function used mainly in mechanism design
- Xbox One S, a video game console by Microsoft
- Xerox Operating System, an operating system for the XDS Sigma line of computers
- Xylooligosaccharide, a polymer of the sugar xylose
- Xos, Inc., an American manufacturer of electric trucks
- XOS Romania a privately held Romanian company operating a classified advertisements website with sections devoted to jobs, housing, for sale, items wanted, services, community service.