O
- (Romenskyi Raion) Omelkove
- (Sumskyi Raion) Opolonske
- (Okhtyrskiy Rayon) Oleksandrivka
- (Okhtyrskiy Rayon) Ovodivka
- (Shostkyns’ka Mis’krada) Orliv Yar
- (Shostkyns’ka Mis’krada) Obiednane
- (Shostkyns’ka Mis’krada) Okip
- (Shostkyns’ka Mis’krada) Olyne
- (Konotops’ka Mis’krada) Otrokhove
- (Shostkyns’ka Mis’krada) Olhyne
- (Shostkyns’ka Mis’krada) Odradne
- (Konotops’ka Mis’krada) Okip
- (Konotops’ka Mis’krada) Ozarychi
- (Konotops’ka Mis’krada) Orikhivka
- (Sumskyi Raion) Omelchenky
- (Romenskyi Raion) Ozerne
- (Sumskyi Raion) Okip
- (Romenskyi Raion) Ovecha
- (Romenskyi Raion) Oleksiivka
- (Romenskyi Raion) Oleshchenkove
- (Okhtyrskiy Rayon) Ovcharenky
- (Sumskyi Raion) Oleksenkove
- (Sumskyi Raion) Ovdianske
- (Sumskyi Raion) Oblohy
- (Sumskyi Raion) Oleksiivka
- (Shostkyns’ka Mis’krada) Ozerny
- (Shostkyns’ka Mis’krada) Ostroushky
- (Sumskyi Raion) Osoivka
- (Shostkyns’ka Mis’krada) Orlivka
- (Konotops’ka Mis’krada) Orlivka