Friesack (; also Friesack/Mark) is a town in the Havelland district, in Brandenburg, in north-eastern Germany. It is situated northeast of Rathenow, and southwest of Neuruppin. It is known for its Mesolithic archaeological site.
During World War II, in September 1943, the Oflag 8 prisoner-of-war camp was relocated from Frauenberg to Wutzetz, present-day district of Friesack. Polish, Greek, Bulgarian and Romanian officers were held in the camp before its dissolution in April 1945.