Hainaut commonly refers to:
- Hainaut (province), the modern Belgian province, part of the Walloon Region (Wallonia)
- the County of Hainaut, or Henegouwen in Dutch, the feudal entity created in 1071 on the order of Henry IV; it overlaps part of northern France with the modern Hainaut province of Belgium
- Hainaut (France) a part of the former province Flanders and Hainaut
- the Hainaut meteorite of 1934, which landed in Nord-Pas-de-Calais near the French-Belgium border