Markéta was the daughter of Mikulas Planský ze Žeberka but her mother is unknown. The date and place of her birth have not been found.
Her husband was Oldřich ze Šternberka. They were married, but the date and place have not been found. Their three known children were Kateřina (?-1465), Smil (?-1433) and Aleš (c1380-1455).