The Partition Sejm (Polish: Sejm Rozbiorowy) was a Sejm lasting from 1773 to 1775 in the Polish–Lithuanian Commonwealth, convened by its three neighbours (the Russian Empire, Prussia and Austria) in order to legalize their First Partition of Poland. During its first days in session, that Sejm was the site of Tadeusz Rejtan's famous gesture of protest against Partition. The Sejm also passed other legislation, notably establishing the Permanent Council and the Commission of National Education. Cardinal Laws were confirmed.

The new legislation was guaranteed by the Russian Empire, giving it another excuse to interfere in the Commonwealth politics if the legislation it favored was changed. Russia was the party most determined to form the Permanent Council, which it saw as further means to control the Commonwealth.

The creation of the Commission of National Education, the Commonwealth's and Europe's first ministry of education, is seen as the proudest and most constructive achievement of the otherwise often-deplored Partition Sejm.