The São Bento Palace (Portuguese: Palácio de São Bento, lit. 'Palace of Saint Benedict') is the seat of the Assembly of the Republic, the parliament of Portugal. It is located in the Estrela district of Lisbon. The building has been home to the succession of Portuguese national parliaments since 1834. São Bento Mansion, the official residence of the Prime Minister of Portugal, is within the grounds of São Bento Palace.

The building was originally a monastery of the Benedictine Order. Construction began in 1598 and was close to completion when the building was damaged by the 1755 Lisbon earthquake. Monasteries in Portugal were dissolved in 1834 and São Bento became national property. The building was repurposed as the meeting place of the Cortes Gerais, the parliament of the new constitutional monarchy of Portugal.

The building was modified to suit its new purpose. The former chapter house of the monks was remodelled into a meeting chamber in 1867, which remains in use today. A major fire in 1895 led to more extensive changes, which produced the current façade.

The Portuguese revolution of 1910 and the formation of the Estado Novo in 1933 replaced the Cortes with different bicameral legislative assemblies, which continued to meet in São Bento Palace. Following the Carnation Revolution in 1974, the building was used for the Constituent Assembly that drafted the current constitution of Portugal, enacted in 1976. The new constitution established the unicameral Assembly of the Republic, which meets in the building.