Johann (John) Georg Hagen (March 6, 1847 in Bregenz, Austria – September 5, 1930 in Rome, Italy), was an Austrian Jesuit priest and astronomer.
Naturalized American citizen he was called to Rome by Pope Pius X in 1906 to be the first Jesuit director of the new Vatican Observatory.
Father Hagen was also the spiritual director of Maria Elizabeth Hesselblad (1870-1957), who was baptized by him on August 15 1902 and eventually was canonized on June 5 2016 by pope Francis.