Robert Thomas Jenkins CBE (31 August 1881 – 11 November 1969) was a Welsh historian and academic.
He moved with his family to Bangor, Gwynedd, when his father was appointed clerk to the registrar of the newly established University College of North Wales.
He was baptised by Thomas Charles Edwards and studied at Bala Grammar School before winning a scholarship to the University College of Wales, Aberystwyth, obtaining a first-class degree in English in 1901.
He then studied history and English at Trinity College, Cambridge before teaching in Llandysul (1904), in Brecon (1904 to 1917) and at the City of Cardiff High School for Boys (1917 to 1930).
Whilst he was a teacher, his interest in history deepened and he began to start writing articles on historical topics.