Hesbaye (French) or Haspengouw (Dutch) (Latinized as Hesbania in medieval documents), is a region spanning the south of the Belgian province of Limburg, the east of the Belgian provinces of Flemish Brabant and Walloon Brabant, and the northwestern part of the province of Liège.

The Limburgish portion contains the cities of Tongeren, Sint-Truiden, Bilzen and Borgloon, while the Brabantian portion includes Tienen, Landen and Zoutleeuw. From the seventh century it was an important fief in the northwestern marches of the Merovingian kingdom of Austrasia. It lay in "that region where the western foreland of the Eifel meets the south-western fringe of silva carbonaria, a woodland frequently mentioned in Frankish historiography." The Merovingian county was consolidated from the old mark Haspinga of which the final -ga element survives in the -gouw of the modern Dutch name: Gau (plural Gaue) was an old Frankish term for a political division, equivalent in its etymology to the French pays.

Hesbania (confusingly spelled Hispania in old documents) was perhaps set apart for Lambertus (born 640), son of Guerin, count of Poitiers (ca. 612 in Austrasia, – 677/87). It was mentioned in the division of territories between Charles the Bald and Louis the German in 870 in the Treaty of Meerssen. In 1040, the Emperor Henry III gave the fief to the prince-bishop Nithard of Liège who integrated it with the Prince-Bishopric of Liège.