The Convocation Sejm of 1764 was a session of the Sejm (parliament) of the Polish-Lithuanian Commonwealth. It took place in Warsaw from 7 May to 23 June, and was a confederated convocation sejm, tasked with preparing a new royal election to fill the throne of the Commonwealth. It carried out a series of reforms to the Commonwealth government.
The Sejm was led by Sejm marshal, Adam Kazimierz Czartoryski. Familia party of Czartoryski magnate family, backed by the Russian Empire (whose military forces were occupying parts of the Commonwealth) forced an election of their candidate (Stanisław August Poniatowski). In protest at the presence of Russian forces, and influence of Russian ambassador to the Commonwealth, Herman Karl von Keyserling, many opposition deputies left the session - in the end the Sejm passed its decisions with only 80 deputies (out of 300) and 7 senators (out of 136). The Sejm approved the cession of the territory of the Republic to Russia, made in the Eternal Peace Treaty of 1686.