Missouri Neighborhoods O
- O'Fallon Park (1)
- O'Fallon St Charles (36)
- Oak Meyer Gardens (2)
- Oak Park Northwest (7)
- Oak Park Southeast (5)
- Oak Park Southwest (6)
- Oak Tree Farm (1)
- Oaks Ridge Meadows (1)
- Oakville (5)
- Old Westport (5)
- Oldham Farms (3)
- Ott-Chrisman (8)
- Outer North Springfield (21)
- Outer Southeast Springfield (35)
- Outer Southwest Springfield (65)