William Lenn (also Lenne or de Lynn; died 1373) was a medieval bishop of Chichester and bishop of Worcester. The name Lenn was the old name for Lynn in Norfolk. Lenn went to Rome in his early life and became a doctor of canon law. He was subsequently made an auditor of causes, in the holy court, by Pope Urban V. In 1356 Lenn was made dean of Chichester Cathedral, then after the death of Bishop Stratford he was selected for the see of Chichester on 16 May 1362, and was consecrated about 18 August 1362.