William d'Aubigny, 1st Earl of Arundel (c. 1109 – October 12, 1176) was son of a senior William d'Aubigny and Maud le Bigod.

The younger William was an important member of Henry I of England's household. After Henry's death he married the widow Queen consort Adeliza, and became lord of Arundel in her right. He was loyal to Stephen of England, who made him Earl of Arundel (more precisely, Earl of Sussex). In 1143 he was also mentioned as Earl of Lincoln in two charters confirming a donation of land around Arundel to the abbey of Affligem in Brabant (representing his wife Adeliza), with William's brother Olivier present.

In 1153 he helped arrange the truce between Stephen and Henry Plantagenet, known as the Treaty of Wallingford, which brought and end to The Anarchy. When the latter ascended the throne as Henry II, he confirmed William's earldom and gave him direct possession of Arundel Castle (instead of the possession in right of his wife he had previously had). He remained loyal to the king during the 1173 revolt of Henry the Young King, and helped defeat the rebellion.

He and Adeliza were parents to William d'Aubigny, 2nd Earl of Arundel and grandparents to William d'Aubigny, 3rd Earl of Arundel.