The Koritnica (]; ), with a length slightly over , is a right tributary of the Soča River. It flows west through the Log Koritnica Valley () south of Mount Mangart and then turns south near Log pod Mangartom, flowing past the Kluže Fortress and through the deep and long Kluže Canyon (), also known as the Koritnica Canyon (). It empties into the Soča southeast of Bovec.