Eochaid mac Domangairt (died ca. 697) was a king of Dál Riata (modern western Scotland) in about 697. He was a member of the Cenél nGabráin, the son of Domangart mac Domnaill and father of Eochaid mac Echdach; Alpín mac Echdach may also be a son of this Eochaid.
He is named in Dál Riata king-lists, the Duan Albanach and the Synchronisms of Flann Mainistrech. In some sources he is called Eochaid Crook-Nose (Riannamail), but modern readings take this is a being a garbled reference to Fiannamail ua Dúnchado rather than an epithet.
The killing of Eochu nepos Domnaill, Eochaid grandson of Domnall Brecc, is reported in the Annals of Ulster for 697.