O18
- 018 (disambiguation)
- 18 (disambiguation)
- 18O (disambiguation)
- Canadian National Class O-18-a
- Curtiss O-18 Falcon
- Delta-O-18
- Hanford Municipal Airport
- List of airports in Oklahoma
- MSC(O)-18
- Minuscule 441
- Minuscule 442
- Naos (hieroglyph)
- O (disambiguation)
- Oxygen-18
- Tondabayashi Station
- U18 (disambiguation)
- Xinzhuang metro station