The Red Orchestra (German: Rote Kapelle, pronounced [ˈʁoːtə kaˈpɛlə] ^ⓘ) was the name given by the Abwehr Section III.F to anti-Nazi resistance workers in Germany in August 1941. It primarily referred to a loose network of resistance groups, connected through personal contacts, uniting hundreds of opponents of the Nazi regime. These included groups of friends who held discussions that were centred on Harro Schulze-Boysen, Adam Kuckhoff and Arvid Harnack in Berlin, alongside many others. They printed and distributed prohibited leaflets, posters, and stickers, hoping to incite civil disobedience. They aided Jews and resistance to escape the regime, documented the atrocities of the Nazis, and transmitted military intelligence to the Allies. Contrary to legend, the Red Orchestra was neither directed by Soviet communists nor under a single leadership. It was a network of groups and individuals, often operating independently. To date, about 400 members are known by name.

The term was also used by the German Abwehr to refer to associated Soviet intelligence networks, working in Belgium, France, United Kingdom and the low countries, that were built up by Leopold Trepper on behalf of the Main Directorate of State Security (GRU). Trepper ran a series of clandestine cells for organising agents. He used the latest technology, in the form of small wireless radios, to communicate with Soviet intelligence.

Although the monitoring of the radios' transmissions by the Funkabwehr would eventually lead to the organisation's destruction, the sophisticated use of the technology enabled the organisation to behave as a network, with the ability to achieve tactical surprise and deliver high-quality intelligence, including the warning of Operation Barbarossa.

To this day, the German public perception of the "Red Orchestra" is characterised by the vested interest in historical revisionism of the post-war years and propaganda efforts of both sides of the Cold War.

For a long time after World War II, only parts of the German resistance to Nazism had been known to the public within Germany and the world at large. This included the groups that took part in the 20 July plot and the White Rose resistance groups. In the 1970s there was a growing interest in the various forms of resistance and opposition. However, no organisation's history was so subject to systematic misinformation, and as little recognised, as those resistance groups centred on Arvid Harnack and Harro Schulze-Boysen.

In a number of publications, the groups that these two people represented were seen as traitors and spies. An example of these was Kennwort: Direktor; die Geschichte der Roten Kapelle (Password: Director; The history of the Red Orchestra) written by Heinz Höhne who was a Der Spiegel journalist. Höhne based his book on the investigation by the Lüneburg Public Prosecutor's Office against the General Judge of the Luftwaffe and Nazi apologist Manfred Roeder who was involved in the Harnack and Schulze-Boysen cases during World War II and who contributed decisively to the formation of the legend that survived for much of the Cold War period. In his book Höhne reports from former Gestapo and Reich war court individuals who had a conflict of interest and were intent on defaming the groups attached to Harnack and Schulze-Boysen with accusations of treason.

The perpetuation of the defamation from the 1940s through to the 1970s that started with the Gestapo was incorporated by the Lüneburg Public Prosecutor's Office and evaluated as a journalistic process that can be seen by the 1968 trial of Nazi judge turned far-right Holocaust denier Manfred Roeder by the German lawyer Robert Kempner. The Frankfurt public prosecutor's office, which prosecuted the case against Roeder, based its investigation on procedure case number "1 Js 16/49" which was the trial case number defined by the Lüneburg Public Prosecutor's Office. The whole process propagated the Gestapo ideas of the Red Orchestra and this was promulgated in the report of the public prosecutor's office which stated:

In the course of time, a group of political supporters of different characters and backgrounds gathered around these two men and their wives. They were united in their active opposition to National Socialism and in their support for communism. Until the outbreak of war with the Soviet Union, the focus of their work was on domestic policy. After that, it shifted more to the field of treason and espionage in favour of the Soviet Union. At the beginning of 1942, the Schulze-Boysen group was finally integrated into the widely ramified network of Soviet intelligence in Western Europe. The value of the intelligence passed on by the Schulze-Boysen group to the Soviet intelligence service cannot be underestimated according to general judgement. All persons who had to deal with this material in their official capacity agree that it was the most dangerous treason organisation uncovered during World War II.... In no... case, however, it is certain that those convicted were only sentenced for high treason and favouring the enemy. The Schulze-Boysen group was first and foremost a spy organisation for the Soviet Union. Since the outbreak of war with Russia, internal resistance took a back seat to espionage work, and it can be assumed that all members were used directly or indirectly for intelligence gathering.