William and his wife Matilda of Flanders had at least nine children.[48] The birth order of the boys is clear, but no source gives the relative order of birth of the daughters.[2]
Robert was born between 1051 and 1054, died 10 February 1134.[48] Duke of Normandy, married Sybil of Conversano, daughter of Geoffrey of Conversano.[145]
Richard was born before 1056, died around 1075.[48]
William was born between 1056 and 1060, died 2 August 1100.[48] King of England, killed in the New Forest.[146]
Henry was born in late 1068, died 1 December 1135.[48] King of England, married Edith of Scotland, daughter of Malcolm III of Scotland. His second wife was Adeliza of Louvain.[147]
Adeliza (or Adelida,[148] Adelaide[147]) died before 1113, reportedly betrothed to Harold II of England, probably a nun of Saint Léger at Préaux.[148]
Cecilia (or Cecily) was born before 1066, died 1127, Abbess of Holy Trinity, Caen.[48]
Matilda[2][148] was born around 1061, died perhaps about 1086.[147] Mentioned in Domesday Book as a daughter of William.[48]
Constance died 1090, married Alan IV Fergent, Duke of Brittany.[48]
Adela died 1137, married Stephen, Count of Blois.[48]
(Possibly) Agatha, the betrothed of Alfonso VI of León and Castile.[w]
There is no evidence of any illegitimate children born to William.[152]