Gertrude of Flanders (c. 1070–1117[1]), was a Countess of Louvain and Landgravine of Brabant by marriage to Henry III, Count of Leuven, and a Duchess of Lorraine by marriage to Theodoric II, Duke of Lorraine.
Gertrude married firstly Henry III, Count of Leuven (died wounded in a tournament in Tournai in 1095), of the House of Reginar.
At Henry's death, his brother Godfrey I succeeded as count and landgrave.
They had four children, probably all daughters (born about 1092-1096), assumingly including: Secondly in 1096 she married Theodoric II, Duke of Lorraine "Thierry" (d. 1115),[4] son of Gérard of Alsace, Count of Metz, Duke of Lorraine (-1070), of the House of Lorraine-Alsace.
Thierry was a widower with a son Simon, and a daughter Gertrude.