18 cities
| City | 2026 Pop. ↓ |
|---|---|
| Oaxaca | 683,128 |
| Orizaba | 511,937 |
| Ojo de Agua | 242,272 |
| Ocotlan | 179,113 |
| Ocosingo | 49,177 |
| Ocozocoautla de Espinosa | 45,779 |
| Ometepec | 28,025 |
| Ocoyoacac | 26,015 |
| Oxkutzkab | 23,096 |
| Ojocaliente | 22,867 |
| Ocotlan de Morelos | 22,163 |
| Ojinaga | 22,128 |
| Ozumba de Alzate | 16,700 |
| Oteapan | 14,925 |
| Oluta | 12,709 |
| Ojuelos de Jalisco | 11,881 |
| Otumba | 10,097 |
| Opopeo | 10,055 |