Geoffrey II (died 1040), Viscount of Châteaudun and Count of Perche (as Geoffrey I), son of Fulcois, Count of Mortagne, and Melisende, Viscountess of Châteaudun.
Some sources say that he became Viscount of Châteaudun following his uncle Hugues II’ appointment as Archbishop of Tours.
He broke with his relatives in the nobility of Blois and began hostilities against Fulbert, Bishop of Chartres.
An unsuccessful attempt to enlist the aid of Theobald III, Count of Blois and Robert the Pious in his quest resulted in his excommunication in 1029.
Geoffrey married Elizabeth or Helvise of Corbon (French: Héloïse de Corbon), daughter of Rainard, Lord of Pithiviers, and his wife Helvise.