The German October (German: Deutscher Oktober) was a plan of the Executive Committee of the Communist International (ECCI) to attempt a communist revolution in the Weimar Republic in October 1923, amidst acute political and economic crises in the country. The Communist Party of Germany (KPD), under the United Front strategy, was directed to enter into coalition governments with the Social Democratic Party of Germany (SPD) in the states of Thuringia and Saxony and utilize their resources to assist the revolution. Despite their efforts, the KPD and ECCI leadership found no support and the plan was called off on 21 October. However, local branches of the KPD in Hamburg and Bremen launched their own insurrections, which were suppressed by the local police.

The entry of the KPD into government in Saxony and Thuringia sparked a crisis in itself. The Reichswehr under Otto Gessler, with the support of the Stresemann cabinet and Reich President Friedrich Ebert, issued an ultimatum demanding the reorganisation of these governments to exclude the Communists. While the Thuringian government agreed, the Saxon government under Erich Zeigner refused, prompting Gessler to deploy the Reichswehr and appoint a Reichskommissar, who deposed Zeigner and occupied the state parliament. The crisis ended with the formation of a new SPD-only government two days later. Donald Pryce posits that the Reich cabinet did not see Saxony or the Communists as a serious threat, but agreed to depose the government in order to appease the Reichswehr and prevent a coup against Berlin assisted by the rogue Bavarian government.

The October events formed a part of the existential crisis of the Weimar Republic in 1923. Three major events in 1923, the occupation of the Ruhr, separatist unrest in the Rhineland and the Palatinate, and the danger of Hitler's far-right beer hall putsch in Bavaria spreading across the country put the Weimar Republic government under extreme pressure. In autumn 1923 the Weimar Republic found itself in political chaos. By the order of the Reich President Friedrich Ebert, a state of emergency was imposed in Germany on September 26, 1923.

Shortly after the Cuno government took office, Belgian and French troops marched into Germany on January 11, 1923, and occupied the Ruhr area. The reason was that Germany did not fulfill her reparations obligations under the Treaty of Versailles by failing to deliver sawn timber, telegraph poles and coal. France, hounded by its foreign creditors, was ready to use force to extract reparations from Germany. This approach was heavily criticized and, among other things, viewed as a policy "close to the edge of the war". France received no support from the Allies. But neither Washington nor London hurried to Germany's aid.

The response of the Cuno government was a policy of "passive resistance": "refusing follow the instructions of the occupiers." As part of the passive resistance, public moments of silence were held and the officials and employees of the Reichsbahn delayed the travel of the coal trains to the west. When this took effect, after a while the French troops began to seize and shut down mines and coking plants and to arrest people. They also took over the railway system. The Reich had to continue to pay the salaries of officials and employees of the Reichsbahn and also give the mining companies large loans so that they could pay the salaries of their workers. This intensified the economic hardship that resulted in the hyperinflation.

At the same time there were strikes and unrest against the Reich government throughout the country, especially in Bavaria. The trade unions and workers' assemblies close to the KPD tried to instigate a general strike against the Cuno government. During this time the KPD was very influential in Saxony, where a social democratic minority government under Erich Zeigner ruled with parliamentary support from the KPD. One consequence was that the paramilitary proletarian hundreds were not banned there, but began in August 1923 to intensify their military exercises and to collect weapons. Moreover, in Thuringia with a social democratic minority government under August Frölich, the KPD was influential and its hundreds were not banned.

Also in autumn 1923 there was separatist unrest in the Rhineland with the aim of founding a Rhenish Republic and breaking away from the German Reich. From October 21, 1923, the separatists brought some Rhenish city and community administrations (e.g. in Aachen, Koblenz, Bonn, Wiesbaden, Trier and Mainz) under their control, partly with the help of the Belgian and French occupation troops. On October 21 they proclaimed a "Rhenish Republic", on November 12 an "Autonomous Palatinate". Since no German military was allowed in the Rhineland according to the provisions of the Versailles Treaty, the Reich government could not use its military to end the uprising. The separatist control was initially recognized by France. The reason for this was that the French wanted to set up buffer states between France and Germany to ensure their future security. This approach was met with disapproval by the German, British and American governments, as well as resistance from the population and led to the end of the uprising by November 1923 after operations by Prussian police and auxiliaries as well as the withdrawal of the French support for the separatists.

The decision to attempt a communist revolution was made in Moscow. Numerous strikes against the right-wing government of Wilhelm Cuno (Cuno strikes) appeared to be the beginning of revolutionary events. The chairman of the Comintern Grigori Zinoviev instructed the KPD on August 15, 1923, to prepare for an approaching revolutionary crisis. Leon Trotsky expressly agreed to this. On August 23, 1923, there was a secret meeting of the Politburo of the Russian Communist Party. The Germany expert Karl Radek also advocated an aggressive approach there. Joseph Stalin was skeptical. The goal of the Soviet plan was that after a victory of the KPD, the highly industrialized "Soviet Germany" would support the economic development of the still predominantly agrarian Soviet Union. The seriously ill Vladimir Lenin no longer played a role. At the end of the meeting, a committee of four members of the Central Committee was formed and immediately sent to Germany for illegal work under false identities. The members were Radek, Józef Unszlicht, Vasily Schmidt and Georgy Pyatakov. Radek was supposed to influence the Central Committee of the KPD to follow the Moscow line, Schmidt was to act as the organizer of the revolutionary cells within the German trade unions, Pyatakov was responsible for general coordination and liaison with Moscow, and Unschlicht was responsible for paramilitary issues and for the formation of a German Cheka planned to operate after the coup. The Soviet ambassador in Berlin, Nikolay Krestinsky, was also supposed to unofficially support their underground work. He was responsible for the administration of the secret funds (400,000 US dollars) in preparation for the German October.