Mittelbau-Dora (also Dora-Mittelbau and Nordhausen-Dora) was a Nazi concentration camp located near Nordhausen in Thuringia, Germany. It was established in late summer 1943 as a subcamp of Buchenwald concentration camp, supplying slave labour from many Eastern countries occupied by Germany (including evacuated survivors of eastern extermination camps), for extending the nearby tunnels in the Kohnstein and for manufacturing the V-2 rocket and the V-1 flying bomb. In the summer of 1944, Mittelbau became an independent concentration camp with numerous subcamps of its own. In 1945, most of the surviving inmates were sent on death marches or crammed in trains of box-cars by the SS. On 11 April 1945, US troops freed the remaining prisoners.

The inmates at Dora-Mittelbau were treated in a brutal and inhumane manner, working 14-hour days and being denied access to basic hygiene, beds, and adequate rations. Around one in three of the roughly 60,000 prisoners who were sent to Dora-Mittelbau died.

Today, the site hosts a memorial and museum.