1610–46) was an Irish physician and poet, author of the first medical work printed in Dublin in 1619.
He was a son of Domhnaill O'Meara, lord of the Ó Meadhra lineage and foster-father to Thomas Butler.
In it, O'Meara describes himself as one of the vates, and claims that Thomas was suckled as a baby by Áine, an Irish goddess.
He returned To Ireland and wrote De Moribus: Pathologia Hereditaria Generalis, a text on hereditary diseases.
In later life, O'Meara and his family broke with the house of Ormond during the Confederation of Kilkenny, in which they favored a complete break with England.