O
- (Pokrovsk Raion) Otradnyy
- (Volnovakha Raion) Otradnyy
- (Kalmiuskyi Raion) Osykove
- (Pokrovsk Raion) Ostrivske
- (Horlivskyi Raion) Orlovo-Ivanivka
- (Pokrovsk Raion) Orlivka
- (Volnovakha Raion) Orlynske
- (Bakhmut Raion) Orikhovo-Vasylivka
- (Kramatorskyi Raion) Orikhuvatka
- (Kalmiuskyi Raion) Orekhov
- (Horlivskyi Raion) Olkhovatka
- (Pokrovsk Raion) Oleksandropil'
- (Volnovakha Raion) Olhynka
- (Horlivskyi Raion) Olenovka
- (Pokrovsk Raion) Oktyabr’skoye
- (Kalmiuskyi Raion) Oleksandrivs'ke
- (Kramatorskyi Raion) Ocheretyne
- (Pokrovsk Raion) Ocheretyne
- (Kalmiuskyi Raion) Obryv
- (Kalmiuskyi Raion) Obilne
- (Kramatorskyi Raion) Ozerne
- (Kramatorskyi Raion) Oleksiievo-Druzhkivka
- (Volnovakha Raion) Oleksiivka
- (Kalmiuskyi Raion) Olenivka