Dirk IV of Valkenburg

Dirk IV (also Thierry IV or Dietrich IV) was the from 1333 until 1346.

Like his father, Dirk joined an alliance against the expansionist Duke John III of Brabant. He took part in the . There were skirmishes in April 1332 at . Following the in March 1334, armistice negotiations began. King Philip VI of France was asked to mediate and ultimately ordered the duke to return Valkenburg, Sittard, Heerlen and the castle of Boutersem to Dirk and recognize his rights.

In the same year that he recovered his lordship (1334), Dirk sold Susteren and to his uncle, , lord of Born. He was recognized as a citizen of the free imperial city of Cologne and served as a counsellor of Count Reginald II of Guelders. In 1336, he married Machteld van Voorne, heiress of Gerard, lord of Voorne and viscount (burgrave) of Zeeland. After the death of his father-in-law, he was granted Zeeland by Count William IV of Holland with the obligation to provide 150 men-at-arms to serve the count.