The following is a list of locomotives built for the Great Northern Railway. As is customary, engine classes are organized according to the man who was locomotive superintendent when the class was introduced, and to whom the design is often attributed. Six men held this post during the existence of the Great Northern Railway. Until 1868 engines were obtained from outside manufacturers, but after this date were increasingly built at the railway's own Doncaster Works, commonly known as the "Plant". Some engines acquired second-hand or from absorbed companies have been omitted from these lists.