The Anjala Conspiracy of 1788 was a plot by Swedish officers, frustrated with King Gustav III's Russian War (1788–1790), to seek peace with Russia. The war had been poorly prepared and unpopular among Sweden's military, especially in Finland, where memories of harsh Russian occupations in the early 18th century were still fresh. Officers believed the war was intended to boost the king's power and diminish that of his noble opponents, leading to growing dissatisfaction.
The conspirators, led by Major General Carl Gustaf Armfeldt, drafted the Liikkala Note in August 1788, seeking peace with Russia and proposing a return to the pre-1743 borders, which would have ceded parts of Karelia back to Sweden. Johan Anders Jägerhorn, one of the conspirators, delivered the note to Catherine the Great in St. Petersburg. However, Jägerhorn also mentioned Finland's potential secession from Sweden, though this was not part of the original conspiracy, leading to accusations of treason.
Following Russia's rejection of significant territorial concessions, the officers formalized their opposition by issuing the Anjala Act, signed by 113 officers. This document called for peace with Russia, convening a parliament (Riksdag), and a return to Sweden's constitutional government from the Age of Liberty (1720–1772), seeking to limit the king's power.
The conspiracy faltered as Jägerhorn's actions were seen as treasonous, and support for King Gustav III grew, particularly from the lower classes. The king used the conspiracy to consolidate his power, arresting the conspirators and strengthening his position through the Union and Security Act of 1789.
The Anjala Conspiracy further alienated the Finnish nobility from Stockholm, contributing to the increasing division between Sweden and Finland. This division ultimately played a role in the events of the Finnish War (1808–1809), which resulted in Finland becoming an autonomous Grand Duchy under Russian rule. The conspiracy also emboldened Russia, which continued to exert influence over Sweden's political and territorial future.