Thomas Butler, 1st Baron Dunboyne (1271 – 9 October 1329) was the third son of Theobald Butler, 4th Chief Butler of Ireland and Joan FitzJohn.
He married Synolda le Petit, daughter of William le Petit[1]
In 1324 he was called to the Irish Parliament (as were intermittently his descendants in the succeeding two centuries before the creation of the Barony of Dunboyne as a lordship of Parliament by patent 1541). He was created 1st Baron Dunboyne in 1324, by prescription. He fought in the Battle of Ardnocher on 9 October 1329 and was killed in action by the Chief of the Clan Geoghegan.