Monbetsu (紋別市, Monbetsu-shi?) is a city located in Okhotsk Subprefecture, Hokkaido, Japan, on the Sea of Okhotsk. The name comes from Ainu Mopet (Quiet River). It is often called Okhotsk-Monbetsu to distinguish it from the town of Monbetsu in Hidaka Subprefecture (different kanji, but same reading).