'Periwig' was a British operation by the Special Operations Executive to simulate the existence of a large-scale anti-Nazi resistance movement within Germany (1944).

Severe restrictions were imposed on the operation by the Special Intelligence Service and the Supreme Headquarters Allied Expeditionary Forces, and the operation was based on the use of several German prisoners of war, specially trained for the purpose but kept in ignorance of their true role, delivered by parachute into Germany with the supposed objects of establishing links with the anti-Nazi German resistance and undertaking sabotage. It was hoped that the men would either surrender themselves or be captured by the Gestapo, and under interrogation reveal their supposed mission. Fake coded wireless transmissions were broadcast to Germany and various pieces of agent equipment, such as code books and wireless receivers, were allowed to fall into the hands of the German authorities.