Muniadona of Castile was a noblewoman from the 11th century, known for her role in the early medieval history of Castile. She was the daughter of Count Sancho García and played a significant part in the political landscape of her time through her marriage to Count García Sánchez III of Navarre. Her marriage helped strengthen ties between Castile and Navarre, two important regions in medieval Spain. Muniadona is also noted for her descendants, who continued to influence the nobility and politics of the Iberian Peninsula in the following centuries.