| City | County | 2026 Pop. ↓ |
|---|---|---|
| Overland Park | Johnson County | 204,818 |
| Olathe | Johnson County | 151,803 |
| Ottawa | Franklin County | 12,736 |
| Osawatomie | Miami County | 4,217 |
| Oaklawn-Sunview | Sedgwick County | 2,877 |
| Osage City | Osage County | 2,770 |
| Oakley | Logan County | 1,963 |
| Ogden | Riley County | 1,650 |
| Oswego | Labette County | 1,612 |
| Oberlin | Decatur County | 1,599 |
| Osborne | Osborne County | 1,236 |
| Oskaloosa | Jefferson County | 1,052 |
| Oxford | Sumner County | 1,036 |
| Overbrook | Osage County | 977 |
| Onaga | Pottawatomie County | 683 |
| Ozawkie | Jefferson County | 613 |
| Olpe | Lyon County | 531 |
| Otis | Rush County | 283 |
| Olsburg | Pottawatomie County | 226 |
| Offerle | Edwards County | 156 |
| Olmitz | Barton County | 90 |
| Olivet | Coffey County | 75 |
| Oketo | Marshall County | 61 |
| Oneida | Nemaha County | 57 |
| Odin | Barton County | 53 |
| Oak Hill | Clay County | 24 |
| Ogallah | Trego County | 15 |
| Opolis | Crawford County | 15 |