O
- (Isoko South) Ogadje
- (Okpe) Ovwori
- (Patani) Ofoni
- (Burutu) Ofuogbene
- (Warri South) Ofia Ekpone
- (Isoko North) Ofagbe
- (Oshimili North) Odozienu
- (Patani) Odorubo
- (Ughelli North) Ododegbo
- (Sapele) Ogiedi
- (Okpe) Odjedi
- (Burutu) Odimodi
- (Warri North) Odibuba
- (Warri South) Ode Itsekiri
- (Oshimili North) Ochonkie
- (Udu) Obusu
- (Ekeremor) Oburigbene
- (Ughelli South) Obrifo
- (Sapele) Obotie
- (Burutu) Obotebe
- (Bomadi) Oboro
- (Aniocha North) Obomkpa
- (Warri South) Obodo
- (Udu) Obodo
- (Aniocha North) Obior
- (Aniocha South) Obi-Onikegu
- (Oshimili South) Obiofu
- (Ukwuani) Obinomba
- (Ndokwa East) Obikwele
- (Ika South) Obi-Iduhon