Oflag X-B was a World War II German prisoner-of-war camp for officers (Offizierlager) located in Nienburg/Weser, Lower Saxony, in north-western Germany.

In March 1940, before the camp was complete, the Polish officers were transferred to a sub-camp of Oflag X-A at Itzehoe in Schleswig-Holstein.

[4] Oflag X-B was opened in May 1940, and was used to hold French officers captured during the battle of France.

About 4 m (13 ft) inside the fence, a strand of electrified wire delimited "no man's land" which it was strictly forbidden to enter.

[5] The administration buildings and accommodation blocks for the guards were located in a compound outside the main gate of the camp, west of the Oflag, and south of the Kaserne.

Generally, the French officers ran much of the camp themselves, organising the cooking of food, and the distribution of fuel, post, and supplies, and also staffed the hospital.

The prisoners performed plays and musical concerts, and open areas were used as vegetable gardens and to breed rabbits for food.

[5] In June 1941 thirteen officers managed to escape through a 50 m (160 ft) tunnel that they had dug from the easternmost hut out under the fence.

[4] Initially Stalag X-C held only French soldiers, but later Poles, Belgians, Romanians and Serbs were sent there.

[4] Stalag X-C housed only about 1,000 prisoners, but there were up to 45,000 men in numerous Arbeitskommando scattered throughout the Weser-Ems region attached to it.

[4] In the immediate post-war period Oflag X-B was used to accommodate displaced persons and refugees.