Simon II de Senlis, Earl of Huntingdon-Northampton

Simon II de Senlis (or Senliz, St. Liz, etc.), 4th Earl of the Honour of Huntingdon and Northampton ( 1098–1153) was an Anglo-Norman nobleman. He was the son of Simon I de Senlis, Earl of Huntingdon-Northampton and Maud, Countess of Huntingdon. He married Isabel, daughter of Robert de Beaumont, 2nd Earl of Leicester and they had a son Simon.

He was prominent in the Anarchy, fighting for Stephen of England in 1141 at the Battle of Lincoln. He continued to support Stephen's side; R. H. C. Davis calls him 'staunch' and 'consistently loyal' and surmises that Simon calculated that if the Empress Matilda won, his earldom of Northampton would be taken over by her uncle David I of Scotland.

Simon was rewarded by becoming Earl of Huntingdon. He died in 1153 just before Henry II of England took over, whereupon the king restored the Earldom of Huntingdon-Northampton to his ally Malcolm IV of Scotland. His widow, Countess Isabel de Beaumont, remarried to baron Gervase Paganell.