Isoko South is a Local Government Area (LGA) in Delta state, Nigeria. Isoko South has its headquarters in Oleh town. It was created on the 23rd of September, 1991 when the defunct Isoko LGA was split into North and South. It has a land mass of 668km2 with a population of 150,836 (1991 Population Census figure). It comprises ten (10) clans and eleven (11) electoral wards.
The clans are Oleh, Aviara, Uzere, Emede, Olomoro, Igbide, Umeh, Erohwa, Enhwe and Irri and each have a Traditional ruler. Isoko South LGA is also one of the major oil producing areas of the state, with Agip having one of its largest fields there. The people are of the Isoko tribe and farming, trading and fishing are the predominant occupations.