The Full Form of CPCL is Chennai Petroleum Corporation Limited.

Chennai Petroleum Corporation Limited (CPCL) a Group company of Indian Oil Corporation (IOCL) is an Indian state-owned oil and gas corporation headquartered in Chennai, India. It was formed as a joint venture in 1965 between the Government of India (GOI), AMOCO and National Iranian Oil Company (NIOC), having a shareholding in the ratio 74%: 13%: 13% respectively. From the grassroots stage CPCL Refinery was set up with an installed capacity of 2.5 million tonnes per year in a record time of 27 months at a cost of Rs. 430 million without any time or cost overrun.

In 1985, AMOCO disinvested in favour of GOI and the shareholding percentage of GOI and NIOC stood revised at 62% and 15.38% respectively. Later GOI disinvested 16.92% of the paid up capital in favor of Unit Trust of India, mutual funds, insurance companies and banks on 19 May 1992, thereby reducing its holding to 67.7%. The public issue of CPCL shares at a premium of Rs. 70 (Rs. 90 to FIIs) in 1994 was oversubscribed to an extent of 27 times and added a large shareholder base of over 90000. As a part of the restructuring steps taken up by the Government of India, Indian Oil Corporation Limited (IOCL) acquired equity from GOI in 2000-01. Currently IOC holds 51.88% while NIOC continued its holding at wax and petrochemical feedstocks production facilities.