Oneok, Inc. is an American diversified corporation focused primarily on the natural gas industry, and headquartered in Tulsa, Oklahoma. The company is part of the Fortune 500 and S&P 500. Oneok was founded in 1906 as Oklahoma Natural Gas Company, but it changed its corporate name to Oneok in December 1980. It also owns major natural gas liquids (NGL) systems due to the 2005 acquisition of Koch Industries natural gas businesses.

Tulsa is the second-most-populous city in the state of Oklahoma, after Oklahoma City, and is the 47th-most-populous city in the United States. The population was 413,066 as of the 2020 census. It is the principal municipality of the Tulsa metropolitan area, a region with 1,034,123 residents. The city serves as the county seat of Tulsa County, the most densely populated county in Oklahoma, with urban development extending into Osage, Rogers and Wagoner counties.