OOG or Oog may refer to:
- Groningen, the capital city and main municipality of Groningen province in the Netherlands
- Oog, a town in the Sool region of Somaliland
- Oog (comics), a giant alien monster that first appeared in Tales of Suspense #27
- Ocean Observation Group, a group that measures and monitors the surface temperature and salinity of the upper 2000 meters of the ocean
- oog, the ISO 639-3 code for Ong, a variant of Ta'Oi language