O
- (Ikwo) Odomowo
- (Afikpo North) Ozizza
- (Izzi) Ozi
- (Ebonyi) Ozante
- (Afikpo North) Ozara-Ukwu
- (Abakaliki) Ovoaba
- (Ebonyi) Otere-Ofie
- (Izzi) Otamnkaliki
- (Izzi) Osokpuru
- (Onicha) Oshiri
- (Izzi) Osebi
- (Ikwo) Opuitumo
- (Izzi) Ope-Afifia
- (Abakaliki) Opamma
- (Ebonyi) Onyikwa
- (Abakaliki) Onuzo
- (Abakaliki) Onu-Kpara
- (Izzi) Onu Anyim
- (Ishielu) Onuankwo
- (Onicha) Onicha
- (Ebonyi) Omunuho
- (Onicha) Omoniko
- (Izzi) Ominyi
- (Ikwo) Omega-Achara
- (Izzi) Olua
- (Abakaliki) Okwefurike
- (Izzi) Okwaraka
- (Ohaukwu) Okwaba
- (Izzi) Okunyeonu
- (Abakaliki) Okpura-Egbu