| City | County | 2026 Pop. ↓ |
|---|---|---|
| Oklahoma City | Cleveland County | 727,550 |
| Owasso | Tulsa County | 44,211 |
| Okmulgee | Okmulgee County | 11,421 |
| Okemah | Okfuskee County | 3,092 |
| Oakhurst | Tulsa County | 1,920 |
| Oologah | Rogers County | 1,372 |
| Okarche | Kingfisher County | 1,207 |
| Okeene | Blaine County | 1,039 |
| Oakland | Carter County | 945 |
| Oilton | Creek County | 906 |
| Okay | Wagoner County | 618 |
| Olustee | Jackson County | 465 |
| Old Green | Adair County | 453 |
| Ochelata | Washington County | 438 |
| Oktaha | Muskogee County | 350 |
| Optima | Texas County | 309 |
| Oaks | Delaware County | 271 |
| Osage | Osage County | 181 |
| Orlando | Logan County | 142 |
| Oak Hill-Piney | Delaware County | 124 |
| Olive | Creek County | 114 |
| Oakwood | Dewey County | 67 |
| Old Eucha | Delaware County | 36 |