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) .
Children
| Name | Birth | Death | Joined with |
| 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) |
Footnotes (including sources)
| ‡ General |