| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Όαση | city | Dytiki Ellada | Greece | 38.08 | 22.34 | 2063 | 2468 |
| Όαση | city | Kriti | Greece | 35.48 | 23.96 | 75 | 20557 |
| Όαση | city | Peloponnisos | Greece | 38.00 | 22.95 | 0 | 6696 |
| Όασις | city | Dytiki Ellada | Greece | 38.08 | 22.34 | 2063 | 2468 |
| Όασις | city | Peloponnisos | Greece | 38.00 | 22.95 | 0 | 6696 |
| Όβγορος | city | Ammochostos | Cyprus | 35.37 | 33.94 | 209 | 728 |
| Όγκουμ-ντονγκ | city | Gyeonggi | Korea, Republic of (South) | 37.66 | 126.91 | 265 | 390290 |
| Όθος | city | Notio Aigaio | Greece | 35.53 | 27.15 | 1669 | 2831 |
| Όλβιο | city | Anatoliki Makedonia kai Thraki | Greece | 41.03 | 24.80 | 49 | 3428 |
| Όλβιον | city | Anatoliki Makedonia kai Thraki | Greece | 41.03 | 24.80 | 49 | 3428 |
| Όλγα | city | Dytiki Ellada | Greece | 37.90 | 21.35 | 75 | 6893 |
| Όλμπανι | city | New Zealand | -36.72 | 174.70 | 173 | 63642 | |
| Όλμπανι | city | New York | United States | 42.65 | -73.76 | 68 | |
| Όλνταμ | city | Oldham | United Kingdom | 53.55 | -2.12 | 830 | 135575 |
| Όλομουτς | city | Olomoucky Kraj | Czech Republic | 49.59 | 17.25 | 830 | 57054 |
| Όλυμπος | city | Attiki | Greece | 37.78 | 23.95 | 830 | 16054 |
| Όλυμπος | city | Notio Aigaio | Greece | 35.74 | 27.17 | 830 | 321 |
| Όλυνθος | city | Kentriki Makedonia | Greece | 40.29 | 23.34 | 36 | 7732 |
| Όμοδος | city | Lemesos | Cyprus | 34.85 | 32.81 | 2509 | 1527 |
| Όμπερν Χιλς | city | Michigan | United States | 42.69 | -83.23 | 994 | |
| Όνειρο | city | Peloponnisos | Greece | 37.93 | 23.03 | 95 | 9341 |
| Όουκλαντ | city | California | United States | 37.80 | -122.27 | 3 | |
| Όουλου | city | Norra Osterbotten | Finland | 65.02 | 25.47 | 49 | 19697 |
| Όργα | city | Keryneia | Cyprus | 35.36 | 33.03 | 839 | 456 |
| Όριο | city | Sterea Ellada | Greece | 38.53 | 24.12 | 150 | 3463 |
| Όριον | city | Sterea Ellada | Greece | 38.53 | 24.12 | 150 | 3463 |
| Όρμα | city | Kentriki Makedonia | Greece | 40.95 | 21.93 | 1046 | 2129 |
| Όρμη | city | Kentriki Makedonia | Greece | 40.95 | 21.93 | 1046 | 2129 |
| Όρμι | city | Qormi | Malta | 35.88 | 14.47 | 32 | 249505 |
| Όρμος Αγίου Ισιδώρου | city | Voreio Aigaio | Greece | 37.75 | 26.59 | 219 | 1265 |
| Όρμος Αιγιάλης | city | Notio Aigaio | Greece | 36.90 | 25.98 | 1669 | 538 |
| Όρμος Κορθίου | city | Notio Aigaio | Greece | 37.77 | 24.95 | 3 | 2350 |
| Όρμος Κουμαιίκων | city | Voreio Aigaio | Greece | 37.70 | 26.75 | 0 | 1854 |
| Όρμος Μαραθοκάμπου | city | Voreio Aigaio | Greece | 37.71 | 26.70 | 0 | 3285 |
| Όρμος Πάχη | city | Attiki | Greece | 37.97 | 23.36 | 0 | 7639 |
| Όρμος Πρίνου | city | Anatoliki Makedonia kai Thraki | Greece | 40.76 | 24.58 | 19 | 1557 |
| Όρνσκολντσβικ | city | Vasternorrland | Sweden | 63.30 | 18.72 | 173 | 2556 |
| Όροβνικ | city | Dytiki Makedonia | Greece | 40.76 | 21.15 | 3349 | 446 |
| Όρος | city | Kriti | Greece | 35.29 | 24.50 | 1669 | 17127 |
| Όσλο | city | Oslo | Norway | 59.92 | 10.75 | 42 | 81893 |
| Όσσα | city | Kentriki Makedonia | Greece | 40.84 | 23.21 | 1866 | 1052 |
| Όσσα | city | Thessalia | Greece | 39.75 | 22.58 | 830 | 3059 |
| Όσσιανη | city | Dytiki Makedonia | Greece | 40.52 | 21.08 | 2509 | 1862 |
| Όσσιανη | city | Kentriki Makedonia | Greece | 41.08 | 22.28 | 3349 | 1942 |
| Όστερβικ | city | Sachsen-Anhalt | Germany | 51.97 | 10.71 | 403 | 3247 |
| Όστιμα | city | Dytiki Makedonia | Greece | 40.74 | 21.20 | 3441 | 433 |
| Όστροβο | city | Kentriki Makedonia | Greece | 40.80 | 21.84 | 2001 | 2266 |
| Ότσο Ρίος | city | Saint Ann | Jamaica | 18.41 | -77.10 | 173 | 11786 |
| Όχθια | city | Dytiki Ellada | Greece | 38.66 | 21.28 | 127 | 5717 |
| Όχθια | city | Peloponnisos | Greece | 37.66 | 21.90 | 2509 | 1525 |
| Όχτια | city | Sterea Ellada | Greece | 39.03 | 21.45 | 1669 | 895 |
| Όχτος | city | Peloponnisos | Greece | 37.05 | 22.90 | 2582 | 688 |