William de Ferrers, 3rd Earl of Derby, was born on an unknown date to Robert de Ferrers, 2nd Earl of Derby (-1162) and Margaret Peverel (c1144-?) and died before 21 October 1190 Siege of Acre (1189–1191) of unspecified causes. He married Sibylla de Braose (-1227) .
|Offspring of William de Ferrers, 3rd Earl of Derby and Sibylla de Braose (-1227)|
|William de Ferrers, 4th Earl of Derby (c1168-c1247)||1168||1247||Agnes de Kevelioch (c1174-1247)|
|Robert de Ferrers (-1227)||1169 England||1227 England||Joan de Boclande (-c1227)|
|Millicent de Ferrers (c1171-c1190)|
|Agatha de Ferrers (c1175-?)|
|Petronella de Ferrers (c1191-aft1237)||1191||1237||Hervey de Stafford (-1237)|