The Duchy of Limburg or Limbourg is a state of the Holy Roman Empire.

Its main territory including the capital Limbourg is today located within the Belgian province of Liège, with a small part in the neighboring province of Belgian Limburg, within the east of Voeren.From about 1020, Limburg Castle serves as the residence of the Counts of Limburg, who in 1100 adopts the ducal title (Herzog in German, Hertog in Dutch) as Dukes of Lower Lorraine, one of the most important and ancient titles in this part of the empire.

The extinction of the line in 1283 sparks the War of the Limburg Succession, whereafter Limburg is ruled by the Dukes of Brabant in personal union, eventually being grouped together with the Brabantian "Overmaas" territories bordering it (including Dalhem, Valkenburg, and Hertogenrade), to be one of the Seventeen Provinces of the Burgundian Netherlands.

Unlike other parts of this province, the lands of the duchy stay intact within the Southern Netherlands, under Habsburg control, after the divisions caused by the Eighty Years' War and the War of the Spanish Succession.

However finally, after the failed Brabant Revolution in 1789, the duchy's history is terminated with the occupation by French Revolutionary troops in 1793.

These lands are reunited within modern Belgium only after the First World War.The duch yis multilingual, being the place where Dutch, French, and German dialects border upon each other and coexist at their geographical extremes, both now and in medieval times.

Its northern and eastern borders are the approximate boundaries of the modern state of Belgium with the Netherlands and Germany, at their "tripoint".

The eastern part, which includes Eupen, is the administrative capital and northernmost part of the modern Belgian German-speaking Ostkantonen.Of the various places known as Limburg, it is the Duchy of Limburg which is the origin of the pungent-smelling soft cheese known as Limburger, and today made in many places.

(In modern Belgium, such cheese is known as Herve cheese, after the town of that name within the duchy.)