Joseph Johnston (20 August 1890 – 1972) was an Irish academic, farmer, writer and politician. He was born in 1890 in Toomog townland, Castlecaulfield, County Tyrone, to John Johnston, a national school teacher, and the former Mary Geddis. He came from a Presbyterian family of Ulster-Scots descent. He was educated at Dungannon Royal School (1902–06), Trinity College Dublin (1906–10, BA (Mod) in Classics) and Lincoln College, Oxford (1910–12).