S-OIL Corporation is a South Korean energy and chemical company headquartered in Seoul, South Korea. Established in 1976, the company has developed into one of the country's major petroleum refining and petrochemical businesses. It operates a large refining and petrochemical complex in Ulsan and has strategic business relationships with international energy companies, including Saudi Aramco.

Its operations cover petroleum refining, petrochemical production, lubricants, and the distribution of petroleum products. S-OIL manufactures and supplies gasoline, diesel, kerosene, petrochemical feedstocks, and other energy-related products for domestic and international markets. The company also invests in advanced refining technologies, operational efficiency, and lower-carbon energy initiatives. Its long-term vision focuses on becoming a competitive, innovative, and trusted energy and chemical company while strengthening its position in the global energy industry.