American brewing company formed in 2008 through the merger of SABMiller PLC and Molson Coors. Its headquarters are in Chicago.

The company's provenance lies with two of the oldest breweries in the United States, Miller Brewing Company and Coors Brewing Company. The former company was founded by Frederick Edward John Miller, who emigrated from Germany in 1854 and the following year began production in the Plank Road Brewery in Milwaukee, Wis. Adolph Coors—along with his partner, Jacob Schueler—started the Golden Brewery in Golden, Colo., in 1873. Despite significant setbacks imposed by prohibition (1920–33) and World War II (1939–45), the two breweries expanded significantly throughout the 20th century.

The tobacco company Philip Morris Inc. obtained controlling interest in Miller Brewing Company in 1970. In 2002 South African Breweries PLC (SAB) purchased Miller Brewing Company from the Altria Group (a holding company created in 1985 that included Philip Morris), creating SABMiller PLC. Three years later Coors Brewing Company merged with Molson Brewing Company, a prominent Canadian brewery, to become Molson Coors. SABMiller and Molson Coors owned at that time the second and third largest brewing operations in the United States, respectively, trailing only Anheuser-Busch Companies, Inc., in production.

In June 2008 SABMiller and Molson Coors entered into a joint venture; the merger, however, did not include the international component of SABMiller or the Molson Coors operations in Canada. MillerCoors thus became one of the two largest brewers in the world, its only rival in size being the company created from the July 2008 merger of InBev and Anheuser-Busch. In addition to its signature Miller and Coors brands, MillerCoors produces numerous popular beverage lines, including Milwaukee's Best, Blue Moon, Leinenkugel's, and the nonalcoholic Zima.