| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Osdhína | city | Ipeiros | Greece | 39.60 | 20.47 | 2509 | 1116 |
| Osenitsa | city | Anatoliki Makedonia kai Thraki | Greece | 41.37 | 24.24 | 1925 | 947 |
| Oslovon | city | Kentriki Makedonia | Greece | 40.85 | 21.85 | 2509 | 1560 |
| Osman Aga | city | Peloponnisos | Greece | 37.00 | 21.68 | 331 | 3756 |
| Osmanitsa | city | Anatoliki Makedonia kai Thraki | Greece | 41.11 | 24.09 | 141 | 12834 |
| Osmanlí | city | Kentriki Makedonia | Greece | 40.36 | 23.26 | 830 | 2235 |
| Osmanlí | city | Anatoliki Makedonia kai Thraki | Greece | 40.88 | 24.19 | 351 | 5393 |
| Osnitsani | city | Dytiki Makedonia | Greece | 40.36 | 21.16 | 3425 | 1940 |
| Ossa | city | Kentriki Makedonia | Greece | 40.84 | 23.21 | 1866 | 1052 |
| Ossiani | city | Kentriki Makedonia | Greece | 41.08 | 22.28 | 3349 | 1942 |
| Ostrovo | city | Kentriki Makedonia | Greece | 40.80 | 21.84 | 2001 | 2266 |
| Ostrovon | city | Kentriki Makedonia | Greece | 40.80 | 21.84 | 2001 | 2266 |
| Ostrovós | city | Thessalia | Greece | 39.87 | 21.47 | 1824 | 1240 |
| Ostítsa | city | Anatoliki Makedonia kai Thraki | Greece | 41.41 | 24.16 | 2040 | 374 |