Eochaid ua Flannacáin (935 - 1004) was an Irish cleric and poet.
Eochaid was the author of more than twenty surviving quasi-historical, genealogical and topographical poems, many of which were incorporated into Lebor Gabala Erenn. He was a member of Clann Sinaich, an ecclesiastical family of Armagh. At the time of his death he was superior (abbot or prior) of Clonfeacle and Lios Aoigheadh (unidentified). One of his sons, and several of his descendants, were abbots of Armagh.
The Annals of Ulster contain Eochaid's obit sub anno 1004, stating:
The obit was accompanied by a stanza commemorating him: