He was the son of Geoffrey V, Viscount of Châteaudun, and Adelicia de Nevers.
Although Adelicia's ancestry is not precisely known, she is likely the daughter of William IV, Count of Nevers, and Eléonore, Countess of Vermandois.
Geoffrey married twice and produced two famous daughters.
Geoffrey and Mabile had three children: Pierre (d. after 1251), a monk at an unknown abbey, Isabelle and Odette.
Geoffrey's second wife was Clemence de Roches, widow of Theobald VI, Count of Blois.