15 cities
| City | County | 2026 Pop. ↓ |
|---|---|---|
| Oak Ridge | Anderson County | 35,328 |
| Oakland | Fayette County | 11,629 |
| Oak Grove | Washington County | 4,496 |
| Oak Hill | Davidson County | 4,290 |
| Oneida | Scott County | 3,916 |
| Oliver Springs | Roane County | 3,496 |
| Olivet | Hardin County | 1,669 |
| Orlinda | Robertson County | 1,034 |
| Orebank | Sullivan County | 956 |
| Obion | Obion County | 955 |
| Ooltewah | Hamilton County | 443 |
| Ocoee | Polk County | 258 |
| Oak Grove | Macon County | 213 |
| Oakdale | Morgan County | 203 |
| Orme | Franklin County | 83 |