Grez-Doiceau (French: [ɡʁe dwaso]; Walloon: Gré; Dutch: Graven [ˈɣraːvə(n)]) is a municipality of Wallonia located in the Belgian province of Walloon Brabant.

The total area is 55.44 km2 which gives a population density of 224 inhabitants per km2.

The municipality consists of the following districts: Archennes, Biez, Bossut-Gottechain, Grez-Doiceau, and Nethen.

The Nobel Prize-winning cytologist and biochemist Christian de Duve (1917–2013) died in Grez-Doiceau.

This Walloon Brabant location article is a stub.