Marcel Callo (6 December 1921 – 19 March 1945) was a French Roman Catholic from Rennes who served in Catholic organizations – in particular the Young Christian Workers (Jocists) – devoted to charitable works to the poor and to communities in general.
Callo served as an apprentice at a print store from the age of thirteen before joining Catholic associations in France.
He was conscripted to serve during World War II and the Gestapo arrested him in 1944 for his Christian activities.
He died in the camps after being forced to do long hours of labour.On account of the fact that he died in harsh camp conditions in hatred of his faith Pope John Paul II presided over his beatification on 4 October 1987.