United Dairy Farmers (UDF) is an American chain of shops offering dairy products as well as coffee and gasoline. UDF was started by Carl Lindner Sr. and his children in 1938. Almost as soon as they started operations, the Lindners began work on building a dairy store. Carl Sr. believed that if he could sell milk through his own store, he would not have to deal with delivery middlemen and thus pass the resulting savings on to customers. The first United Dairy Farmers store, at 3955 Main Avenue (now Montgomery Road) in Norwood, Ohio, a suburb of Cincinnati, opened on May 8, 1940.

Today, the chain has stores throughout the Greater Cincinnati area as well as Dayton, and Columbus. Many UDF stores also operate a gas station and a convenience store. Since 2001, many locations have sold gasoline under the Mobil brand, but are now supplying their own fuels via purchasing through independent wholesalers.