Barrios de Texas O
- O'Shea Keleher (3)
- Oak Forest-Garden Oaks (129)
- Oak Grove (3)
- Oak Hills (8)
- Oak Lake (8)
- Oak Lawn (153)
- Oak Park/Northwood (15)
- Oakhurst (2)
- Oakhurst (3)
- Oakwell Farms (5)
- Offatts Bayou (13)
- Old East Dallas (133)
- Old Silk Stocking Historic District (9)
- Old West Austin (16)
- Olmos Park Terrace (3)
- Onion Creek (39)
- Original Town (11)
- OST-South Union (155)
- Outer Comal (267)
- Outer Corpus Christi (2)
- Outer East Fort Worth (70)
- Outer Mission Alton (57)
- Outer N Richland Hill/Haltom City (35)
- Outer Northwest (78)
- Outer Socorro (2)
- Outer West Dallas (31)