Warner of Grez, French nobleman, relative of Godfrey of Bouillon

Warner of Grez Count of Grez, was a French nobleman from Grez-Doiceau, currently in Walloon Brabant in Belgium. He was one of the participants in the army of Godfrey of Bouillon of the First Crusade, and died in Jerusalem a year after the crusade ended. His brother Henry is also listed as a Count of Grez and accompanied Warner on the First Crusade.

Godfrey of Bouillon was a preeminent leader of the First Crusade, and the first ruler of the Kingdom of Jerusalem from 1099 to 1100. Although initially reluctant to take the title of king, he agreed to rule as prince (princeps) under the title Advocatus Sancti Sepulchri, or Advocate of the Holy Sepulchre.