O
- (Bashtanka Raion) Orlovets
- (Bashtanka Raion) Oleksandrivka
- (Mykolayiv urban raion) Osetrivka
- (Bashtanka Raion) Otradne
- (Mykolayiv urban raion) Ostapivka
- (Mykolayiv urban raion) Oleksandrivka
- (Mykolayiv urban raion) Oleksandrivka
- (Bashtanka Raion) Odradne
- (Voznesensk Raion) Orlove Pole
- (Mykolayiv urban raion) Ostrovske
- (Pervomaysk Raion) Ostapivka
- (Voznesensk Raion) Ochakivske
- (Voznesensk Raion) Ozerynivka
- (Voznesensk Raion) Oleksandrodar
- (Mykolayiv urban raion) Olenivka
- (Bashtanka Raion) Ozerivka
- (Mykolayiv urban raion) Ostrivka
- (Pervomaysk Raion) Ostrohirske
- (Voznesensk Raion) Oleksandrivka
- (Voznesensk Raion) Oeksandrivka
- (Bashtanka Raion) Oleksandrivka
- (Voznesensk Raion) Obukhivka
- (Pervomaysk Raion) Onyskove
- (Mykolayiv urban raion) Ozerne
- (Voznesensk Raion) Olhopil
- (Pervomaysk Raion) Ocheretnya
- (Bashtanka Raion) Oleksandrivka
- (Mykolayiv urban raion) Olshanske
- (Voznesensk Raion) Oleksandrivka