Laurentius Siemer (; born Josef Siemer, 8 March 1888 in Elisabethfehn/Barßel – 21 October 1956 in Cologne) was a Dominican priest, and Provincial of the Dominican Province of Teutonia, Germany during the Nazi period. A significant figure in Catholic resistance to Nazism, he became a spiritual leader of the German Resistance movement and was imprisoned by the Nazis. Implicated in the July Plot, he survived the war in hiding and assisted in drafting Germany's post war constitution. In later life he became a TV celebrity.
