The use of milk in a wide range of products has resulted in the development of a wide range of dairy ingredients for use in dairy and non-dairy foods, as well as non-food products. These ingredients range from commodity ingredients, for example, milk powder and whey powder, to milk protein ingredients, such as caseins, caseinates, whey protein ingredients, milk protein concentrates (MCPs) and milk protein hydrolysates. Furthermore, lactose and lactose derivatives, for example, lactulose, lactobionic acid and the prebiotic galactooligosaccharides, and milk fat globule membrane material fractions, may also be produced. This chapter reviews the main dairy ingredients and their applications.