Sir Osmond Thomas Grattan Esmonde, 12th Baronet (4 April 1896 – 22 July 1936) was an Irish diplomat and Cumann na nGaedheal (and later Fine Gael) politician. He was born in Ballynastragh, Gorey, County Wexford in 1896, the eldest son of Sir Thomas Esmonde. He was educated at Mount St Benedict School in Gorey; and the Downside School. He attended Balliol College, Oxford and University College Dublin, though he did not graduate from either. He never married and was succeeded in the baronetcy by his uncle .