Pádraig Ó Fathaigh (1879–1976) was a member of the Gaelic League and an Intelligence Officer of the Irish Republican Army.
A native of Lurgan, Gort, County Galway, Ó Fathaigh was the fifth of six children (and third son) of Laurence and Brdget Ó Fathaigh. Like most of their neighbours, the family were tenant farmers "who lived in a three-roomed house and raised grains, root crops and livestock for sale at local markets. They also maintained a few outbuildings for their animals, indicating that the family was able to invest in some improvements on their farm." Growing up amid the Irish Land War and Home Rule, Ó Fathaigh – whose family spoke Irish at home – joined the Gaelic League. He was certified to teach Irish in national schools in 1907 and two years later became the full-time múinteoir taistil (travelling teacher) for the Gort area. He regularly cycled all over the district each week, his night classes been as large as 150 pupils.
He joined the Irish Volunteers in 1914, possibly becoming a member of the Irish Republican Brotherhood around the same time. His older brothers, Mícheál and Seán were also Volunteers, while their youngest sister, Mary, was secretary of the local Cumann na mBan. Liam Mellows was a regular visitor to the family home. His participation in the Easter Rebellion of 1916 was cut short by his arrest at Kinvara presbytery, while the main group of over six hundred Galway volunteers gathered near Athenry and Oranmore under Liam Mellows and Larry Lardner.
After the failure of the rising, Ó Fathaigh served time for penal servitude in England till released in 1917. With the start of the Irish War of Independence he was on the run, serving as an intelligence officer.