Thai Oil Public Company Limited or simply Thaioil is a Thai public company. It is listed on the Stock Exchange of Thailand. It is a subsidiary of PTT Group. The company was founded on 3 August 1961 as Oil Refinery, Ltd. Thaioil is the largest oil refinery in Thailand.
Thai Oil Public Co. Ltd. is engaged in the production of petroleum products for domestic distribution. The company is also involved in petroleum refining, pipeline transportation, and carbon black and paraxylene production. It operates through the following segments: Oil Refinery, Lube Base Oil Refinery, Petrochemical, Power Generation, Oil and Chemical Products Transportation Services, Solvent, Ethanol and Other. Thai Oil Public was founded in 1961 and is headquartered in Bangkok, Thailand.