Lethlobar mac Echach was a Dál nAraide king of the Cruthin in Ulaid, an over-kingdom in Ireland. He was the son of Eochaid Iarlaithe mac Lurgain, a previous king. He belonged to the main ruling dynasty of the Dál nAraide known as the Uí Chóelbad based in Magh Line. He ruled from 708 to 709.