International Dairy Queen, Inc. (DQ) is an American multinational fast food restaurant chain founded in 1940 and headquartered in Bloomington, Minnesota. The first Dairy Queen was owned and operated by Sherb Noble and opened on June 22, 1940, in Joliet, Illinois. It serves a variety of hot and fried food, as well as original frozen dairy products that vary from location to location.

The soft-serve formula was first developed in 1938 by John Fremont "J.F." McCullough and his son Alex. They convinced friend and loyal customer Sherb Noble to offer the product in his ice cream store in Kankakee, Illinois. On the first day of sales, Noble sold more than 1,600 servings of the new dessert within two hours. Noble and the McCulloughs went on to open the first Dairy Queen store in 1940 in Joliet, Illinois. It closed in the 1950s, but the 501 N Chicago Street building is a city-designated landmark.

Since 1940, the chain has used a franchise system to expand its operations globally. The first ten stores in 1941 grew to 100 by 1947, 1,446 in 1950, and 2,600 in 1955. Canada's first location was at a "quick freeze plant" in Melville, Saskatchewan, 1952, followed by a standalone store in Estevan in 1953. The oldest surviving freestanding location opened in Port Colborne, 1954.

The company became International Dairy Queen, Inc. (IDQ) in 1962. IDQ is the parent company of American Dairy Queen Corporation (often abbreviated "Am. D.Q. Corp." in the chain's legal disclaimers), Dairy Queen Canada Inc., and other entities that franchise the Dairy Queen concept.

In 1987, IDQ bought the Orange Julius chain. IDQ was acquired by Berkshire Hathaway in 1998. In the 1990s, investors bought Dairy Queen stores that were individually owned, intending to increase profitability through economies of scale. Vasari, LLC became the second-largest Dairy Queen operator in the country and operated 70 Dairy Queens across Texas, Oklahoma, and New Mexico. When stores were not profitable, the firm closed them. On October 30, 2017, Vasari LLC filed for bankruptcy and announced it was closing 29 DQ stores, including ten in the Texas Panhandle.

In the US, the state with the most Dairy Queen restaurants is Texas. Using the 2010 census, the state with the most Dairy Queen restaurants per person is Minnesota. At the end of fiscal year 2014, Dairy Queen reported over 6,400 stores in more than 25 countries; about 4,500 of them (approximately 70%) were in the United States.

Dairy Queens were a fixture of social life in small Midwestern and Southern United States towns during the 1950s and 1960s. They have often been reflected in stories and memoirs of small-town America, as in Walter Benjamin at the Dairy Queen: Reflections at Sixty and Beyond by Larry McMurtry, Dairy Queen Days by Robert Inman, Chevrolet Summers, Dairy Queen Nights by Bob Greene, and The Outsiders by S. E. Hinton including the film adaptation by Francis Ford Coppola.

The company's stores are operated under several brands, all bearing the Dairy Queen logo and carrying the company's signature soft-serve. "Brazier" locations, with expanded food menus and second floors for storage, are recognizable by their red mansard roofs.