Raymond-Joseph Loenertz (10 June 1900 – 31 August 1976) was a medievalist from Luxembourg. He entered the Dominican Order and since 1930 worked in the Dominican Historical Institute.
His work focused on the history of the Dominican Order and the relations between the Byzantine Empire and the Latin West. He published the letters of the Byzantine theologian Manuel Kalekas (Vatican City 1950) and of the theologian and statesman Demetrios Kydones (2 vv., Vatican City 1956-1960) and, with Antonio Garzya, works by Procopius of Gaza.