The Pereiaslav Agreement or Pereyaslav Agreement was an official meeting that convened for a ceremonial pledge of allegiance by Cossacks to the Tsar of Russia in the town of Pereiaslav, in central Ukraine, in January 1654. The ceremony took place concurrently with ongoing negotiations that started on the initiative of Hetman Bohdan Khmelnytsky to address the issue of the Cossack Hetmanate with the ongoing Khmelnytsky Uprising against the Polish–Lithuanian Commonwealth and which concluded the Treaty of Pereiaslav. The treaty itself was finalized in Moscow in April 1654.

The Tsardom of Russia, also known as the Tsardom of Muscovy, was the centralized Russian state from the assumption of the title of tsar by Ivan IV in 1547 until the foundation of the Russian Empire by Peter the Great in 1721.