Reginald Thomas Foster (November 14, 1939 – December 25, 2020) was an American Catholic priest and friar of the Order of Discalced Carmelites. From 1970 until his retirement in 2009, he worked in the Latin Letters section of the Secretariat of State in the Vatican. He was an expert in Latin literature and an influential teacher of Latin, including 30 years at the Gregorian University, Teresianum, Urbanianum in Rome and free summer courses that continued when he retired to Milwaukee. ()