Liudolf of Brunswick (about 1003 – 23 April 1038) was margrave of Frisia, count of Brunswick, count in the Derlingau and the Gudingau. He was a member of the Brunonen family.
Liudolf was a descendant of the Saxon family of the Brunonen. He was a son of Bruno I, Count of Brunswick, and Gisela of Swabia. The later Roman Emperor Henry III was his half brother. He married Gertrude and had four children. The Friesian counties Oostergo, Zuidergo and Westergo were controlled by him. Until the end of his life he administered the Frisian areas, and for two more generations the Brunonen family line inherited the title. How the Brunonen came to their position in the counties is not known. There is a theory that Liudolf took advantage of the reign of violence between Friesland Vlie and Lauwers of the counts of Holland. Not much is known about his life. He died in 1038 and was succeeded by his son, Bruno II. His daughter Matilda married Henry I of France, the widower of her aunt. One popular theory of the origins of Agatha, wife of Edward the Exile makes her another daughter.
Liudolf and his wife Gertrud had the following children: