Lionel de Welles, 6th Baron Welles, KG (c.1406 – 29 March 1461) was an English peer who served as Lord Lieutenant of Ireland and Joint Deputy of Calais. He was slain fighting on the Lancastrian side at the Battle of Towton, and was attainted on 21 December 1461. As a result of the attainder, his son, Richard Welles, 7th Baron Welles, did not succeed him in the barony of Welles until the attainder was reversed by Parliament in June 1467.