The Lomami River is a major tributary of the Congo River in the Democratic Republic of the Congo. The river is approximately 1,500 km long. It flows north, west of and parallel to the upper Congo.

The Lomami rises in the south of the country, near Kamina , and flows north through Lubao, Tshofa , Kombe , Bolaiti , Opala and Irema before joining the Congo at Isengi .