Joanna of Brabant was a medieval noblewoman born around 1322 in Brabant, a region in present-day Belgium. She was the daughter of John III, Duke of Brabant and Marie of Évreux. Joanna became the Duchess of Brabant through her marriage to Wenceslaus I, Duke of Luxembourg in 1345, which strengthened political ties between their territories. Joanna was known for her role in the governance of Brabant and her efforts to maintain peace during her husband's absence. After Wenceslaus's death in 1383, she continued to influence the region until her own death in 1406, leaving a legacy of stability in the duchy.