KOS
KOS may refer to:
- KOS Media, providing county wide and local regional publications in Kent
- Kill on sight
- Kingdom of Sorrow a Sludgecore band from New Orleans
- Knowledge Organization Systems, a generic term used in Knowledge organization
- KolibriOS, open source x86 operating system
- KOS (Yugoslavia), the counterintelligence service of the Yugoslav People's Army
- Kickoff specialist, a position in American football and Canadian football responsible for handling kickoff duties
- Kid operating system, a French software project