Oil and Natural Gas Corporation Limited (ONGC) is an Indian multinational oil and gas company headquartered in Dehradun, India. It is a public sector undertaking (PSU) of the Government of India, under the administrative control of the Ministry of Petroleum and Natural Gas. It is India's largest oil and gas exploration and production company.

ONGC was founded on August 14, 1956 by Government of India, which currently holds a 69.23 percent equity stake. It is involved in exploring for and exploiting hydrocarbons in 26 sedimentary basins of India, and owns and operates over 11,000 kilometers of pipelines in the country.

Its international subsidiary ONGC Videsh Ltd (OVL) currently has projects in 15 countries. ONGC has discovered 6 of the 7 commercially-producing Indian Basins, in the last 50 years, adding over 7.1 billion tonnes (BT) of in-place oil and gas volume of hydrocarbons in Indian basins.