| Orekhovo-Borisovo Yuzhnoye |
Russia |
| Oeiras |
Portugal |
| Olsztyn |
Poland |
| Osmaniye |
Turkey |
| Oldenburg |
Germany |
| Oyama |
Japan |
| Osnabruck |
Germany |
| Oshawa |
Canada |
| Obihiro |
Japan |
| Odense |
Denmark |
| Ogaki |
Japan |
| Ordu |
Turkey |
| Oxford |
United Kingdom |
| Ocumare del Tuy |
Venezuela |
| Odivelas |
Portugal |
| Osorno |
Chile |
| Odintsovo |
Russia |
| Okinawa |
Japan |
| Ozamiz City |
Philippines |
| Ome |
Japan |
| Ouargla |
Algeria |
| Onomichi |
Japan |
| Opole |
Poland |
| Orebro |
Sweden |
| Omiyacho |
Japan |
| Osaki |
Japan |
| Ouahigouya |
Burkina Faso |
| Orekhovo-Zuyevo |
Russia |
| Ondjiva |
Angola |
| Orleans |
France |
| Obninsk |
Russia |
| Oktyabr'skiy |
Russia |
| Osmanabad |
India |
| Otaru |
Japan |
| Oshu |
Japan |
| Olmaliq |
Uzbekistan |
| Omuta |
Japan |
| Ourinhos |
Brazil |
| Orsha |
Belarus |
| Ourense |
Spain |
| Onojo |
Japan |
| Oued Zem |
Morocco |
| Olomouc |
Czechia |
| Oum el Bouaghi |
Algeria |
| Obu |
Japan |
| Oulad Teima |
Morocco |
| Owariasahi |
Japan |
| Ouidah |
Benin |
| Osijek |
Croatia |
| Okegawa |
Japan |