Dr. Johann Gruber (October 20, 1889 - April 7, 1944), also known as "Papa Gruber" and "The Saint of Gusen", was an Austrian Roman Catholic priest who was imprisoned in the Mauthausen-Gusen concentration camp from 1940 until his death in April 1944. In the concentration camp, Gruber helped many others survive by raising funds from outside the camp and bribing the SS men and kapos in order to organise the delivery of food to starving inmates.