Udo IV (died 15 February 1130), Margrave of the Nordmark and Count of Stade (as Udo V) and Count of Freckleben, son of Rudolf I, Margrave of the Nordmark, and Richardis, daughter of Hermann von Sponheim, Burgrave of Magdeburg.
When Henry II died on 4 December 1128 without an heir, his uncle Albert the Bear hoped to become margrave, but Udo was favored by Emperor Henry III and assumed control of the margraviate.
In 1128, Udo married Mathilde, the daughter of Herman I, Count of Winzenburg.
Further complicating the family relations, her brother Herman II was the third husband of Danish queen Lutgard of Salzwedel, daughter of Rudolf I and therefore sister of Udo.
He left no male heir and was succeeded as margrave by Conrad of Plötzkau.