The National Iranian South Oil Company (NISOC) is a government-owned corporation under Iran's Ministry of Petroleum and a subsidiary of the National Iranian Oil Company (NIOC). Established in 1971, NISOC is Iran's largest oil producer, generating around 3 million barrels of crude oil daily. The company operates in a vast area exceeding 400,000 square kilometers, primarily in southwestern provinces such as Khuzestan and Bushehr.

NISOC manages some of the world's largest onshore oil fields, including the Ahvaz Field, Gachsaran, and Maroun. These fields are crucial to Iran's energy sector, contributing significantly to the country's crude oil and natural gas production. The company focuses on exploration, development, and production of oil and gas, as well as managing oilfields and providing upstream services. NISOC plays a vital role in supplying both domestic and international energy markets. Its operations support Iran's national oil export and domestic energy supply chains.