Oka or OKA may refer to:
- Oka cheese, a Canadian cheese
- Oka (mass), an Ottoman unit of weight equal to 1.2829 kilograms
- Oca or Oca, the root vegetable Oxalis tuberosa
- MXY-7 Ohka (also spelled Ōka), a Japanese kamikaze aircraft in World War II
- R-400 Oka, a theatre ballistic missile deployed by the Soviet Union
- 16494 Oka, an asteroid
- Oka Crisis, a land dispute between the Mohawk Nation and the town of Oka, Canada
- Naha Airport by IATA airport code
- Okay Airways by ICAO airline code
- Tropical Storm Oka, a Pacific storm in 1987
- Oka (surname), a Japanese surname