Standard Oil of Ohio or Sohio was an American oil company that was acquired by British Petroleum, now part of BP.

It was one of the successor companies to Standard Oil after the antitrust breakup in 1911. Standard Oil of Ohio was the original Standard Oil company founded by John D. Rockefeller.

BP took majority ownership of the company in the 1970s in return for its share of the Prudhoe Bay oilfield in Alaska. In 1987, after all other Standard Oil descendants had minimized use of the name Standard, Standard of Ohio, proud to be the original, sought to corporately rebrand itself under the Standard name while continuing to use the Sohio brand and others to sell gas in Ohio. The company used the same logo, but with Boron as the name in other states. However, the next year BP bought out the minority interest in Sohio and renamed all the Sohio and Boron stations 'BP' in 1991.

When BP merged with Amoco, its American headquarters moved from the former Standard Oil building on Public Square in Cleveland, Ohio to Chicago.