Henry O'Keane (3 February 1763 – 6 July 1817) was an Irish catholic priest and French army officer.
O'Keane was born at Kilcummin, Killala, County Mayo, one of at least three sons to a cowherd on the Tyrawley estate.
O'Keane became a captain in the 65th regiment, and a member of the staff of Jean Joseph Amable Humbert, for whom he served as a local liaison when the French landed at Killala on 22 August 1798 (he spoke Irish and French better than English).
Church of Ireland Bishop Joseph Stock praised his actions during the rebellion, stating that "his language breathed nothing but mildness and liberality, and indeed his behaviour was suitable, for he exerted himself on all occasions to protect the loyalists and frequently with the greatest effect."
He returned to France, apparently having "carried off from Dublin another man's wife", serving in Germany and Portugal.