Josef Kramer (November 10, 1906 – December 14, 1945) was the commander of Bergen-Belsen concentration camp, who was convicted of war crimes and hanged in Hameln prison after World War II.

Kramer was born in Munich and joined the Nazi Party in 1931 and the SS in 1932. His SS training led him into work as a prison guard and, after the outbreak of war, as a concentration camp guard. He was trained at Auschwitz and also worked at Dachau and Birkenau. In 1940 he accompanied Rudolf Höß (who later trained Kramer at Auschwitz) to inspect Auschwitz as a possible site for a new synthetic coal oil and rubber plant, which was a vital industry in Germany, given its shortage of oil. Kramer soon became notorious among his subordinates as a harsh taskmaster. One of the defendants at the Frankfurt Trial, Dr. Franz Lucas, testified that he tried to avoid assignments given him by Kramer by pleading stomach and intestinal disorders. When Dr. Lucas saw that his name had been added to the list of selecting physicians for a large group of inmates transferred from Hungary, he objected strenuously. Kramer reacted sharply: "I know you are being investigated for favouring prisoners. I am now ordering you to go to the ramp, and if you fail to obey an order, I shall have you arrested on the spot".

In August 1943 Kramer received 80 inmates who were to be killed with gas. With the help of the SS he had the women stripped, and once naked, had them herded into the gas chambers. He later testified "When the door closed they began to scream. I put in a small amount of salt through a tube and looked through a peephole to see what happened. The women breathed about a minute before they fell to the floor." Kramer repeated this until all were dead. When asked how he felt about this he said "I had no feelings in carrying out these things because I had received an order. That, incidentally, is the way I was trained."

In late 1944 Kramer was transferred from Birkenau to Belsen, near the village of Bergen. Belsen had originally served as a temporary camp for those leaving Germany, but during the war had been expanded to serve as a convalescent depot for the ill and displaced people from across north west Europe. Although it had no gas chambers, Kramer's rule was so harsh that he became known as the 'Beast of Belsen'. As Germany collapsed administration of the camp broke down, but Kramer remained devoted to bureaucracy. On March 1, 1945, he filed a report stating that of the 42,000 inmates in his camp, 250-300 had died from "typhus". On March 19, the number of inmates rose to 60,000 as the Germans continued to evacuate camps that were soon to be liberated by the Allies. As late as the week of April 13, some 28,000 additional prisoners were brought in.

With the collapse of administration and many guards fleeing to escape retribution, roll calls were stopped and the inmates were left to their own devices. Corpses rotted everywhere, and rats attacked the living too weak to fight them off. Kramer remained even when the British arrived to liberate the camp. He remained indifferent and callous, and took them on a tour of the camp to inspect the 'scenes'. Piles of corpses were lying all over the camp, mass graves were filled in, and the huts were filled with prisoners in every stage of emaciation and disease.

Kramer and 44 others were tried in the Belsen Trial by a British military court at Lüneburg. He was sentenced to death on November 17, 1945, and hung by Albert Pierrepoint shortly afterwards.