Russo-Prussian alliance

The Russo-Prussian alliance signed by the Kingdom of Prussia and the Russian Empire on 11 April 1764. It was pivotal to the people of Prussia and Russia, and it followed the end of the Seven Years' War. The alliance agreement expanded on the Treaty of Saint Petersburg of 1762, which ended the war between those two countries.

It was a defensive alliance, in which each party declared it would protect the territorial stability of the other. It further allowed both countries to intervene in the Polish–Lithuanian Commonwealth, which was one of the primary intentions of the treaty.

The treaty also allowed Prussia and Russia to exercise better control over the Polish–Lithuanian Commonwealth; both parties agreed to prevent the election of a third king from the House of Wettin. The two countries thus worked together to ensure the election of their own candidate, Stanisław August Poniatowski, later that year.

The treaty also included a provision allowing the signatories to intervene in Poland in case of an unapproved regime change. In fact, the two powers, together with Austria, would intervene jointly in Poland following the War of the Bar Confederation, resulting in the First Partition of Poland in 1772.