Coos could refer to:
- Coos (tribe), a Native American tribe from the U.S. state of Oregon
- Coos Bay, an inlet on the coast of Oregon
- Coos Bay, Oregon, a small city on Coos Bay
- Coos (Abenaki tribe), a Native American tribe from New England
- Coos County, New Hampshire, a county in the U.S. state of New Hampshire
- Coos County, Oregon, a county in Oregon
- Coos River, a river in Oregon
- Kos, an island SW of Asia Minor