Demos may refer to:
- Demos, a rhetorical term for the population of an ancient Greek state
- Deme or Demoi, the term for an ancient subdivision of Attica, Greece
- Demos/Demoi, the name for a specific type of subdivision or municipality in modern Greece; an administrative area covering a city or several villages together
- Demos (UK think tank), London based public policy research organisation and publisher
- Demos (U.S. think tank), a non-partisan public policy research and advocacy organization
- Democratic Opposition of Slovenia, DEMOS coalition, Slovenia
- Eindhovense Studentenvereniging Demos, a student association in Eindhoven, Netherlands
Demos may also refer to:
- Demos (Crosby, Stills & Nash album), 2009
- Demos (Imperial Drag album), 2005
- Demos (Matt Skiba album)
- Demos (film), a 1921 silent film
- DEMOS, a Soviet Unix-like operating system
- Demos Commander, an Orthodox File Manager for Unix-like systems
- Deimos (moon), one of the two moons of Mars
- The Demos, American rock band