Stilton is an English cheese, produced in two varieties: Blue, which has Penicillium roqueforti added to generate a characteristic smell and taste, and White, which does not. Both have been granted the status of a protected designation of origin (PDO) by the European Commission, requiring that only such cheese produced in the three counties of Derbyshire, Leicestershire and Nottinghamshire may be called Stilton. The cheese takes its name from the village of Stilton, now in Cambridgeshire, where it has long been sold, but cannot be made because it is not in one of the three permitted counties.

Cheese is a dairy product produced in a range of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk. During production, milk is usually acidified and either the enzymes of rennet or bacterial enzymes with similar activity are added to cause the casein to coagulate. The solid curds are then separated from the liquid whey and pressed into finished cheese. Some cheeses have aromatic molds on the rind, the outer layer, or throughout.