Gislebert (or Gilbert) of Mons (c. 1150 – 1225) was the Flemish chronicler whose Chronicon Hanoniense (Chronicle of Hainaut) is an essential eyewitness source for events affecting his patron Baldwin V, Count of Hainaut.
Gislebert became a clerk, and obtained the positions of provost of the churches of St. Germanus at Mons and St. Alban at Namur, in addition to several other ecclesiastical appointments. In official documents he is described as chaplain, chancellor or notary, of count Baldwin (d. 1195), who employed him on important business. After 1200 Gislebert wrote the Chronicon Hanoniense, a history of Hainaut and the neighboring lands from about 1050 to 1195, which is specially valuable for the latter part of the twelfth century. Aside from the light it sheds on the life and times of Baldwin, Gislebert provides significant information about persons and affairs within France and the Empire, particularly Count Philip, Count of Flanders, Philip Augustus of France and Emperor Frederick Barbarossa. Gislebert's concerns for noble marriages make his chronicle an irreplaceable source for genealogical information, and in passing he gives details of the crusaders, politics, noble women, the lives of saints, relationships between lord and tenant, traditions and customs and especially military matters, with detailed accounts of sieges, campaigns and tournaments.