Barrios de Texas O
- O'Shea Keleher (7)
- Oak Forest-Garden Oaks (162)
- Oak Grove (4)
- Oak Hills (7)
- Oak Lake (14)
- Oak Lawn (174)
- Oak Park/Northwood (16)
- Oakhurst (3)
- Oakhurst (4)
- Oaklawn (3)
- Oakwell Farms (5)
- Offatts Bayou (13)
- Old East Dallas (159)
- Old Silk Stocking Historic District (7)
- Old Town Spring (3)
- Old West Austin (13)
- Olmos Park Terrace (8)
- Onion Creek (40)
- Original Town (22)
- OST-South Union (199)
- Outer Corpus Christi (4)