The Ajuda National Palace (Portuguese: Palácio Nacional da Ajuda) is a neoclassical monument in the civil parish of Ajuda in the city of Lisbon, central Portugal. Built on the site of a temporary wooden building constructed to house the Royal family after the 1755 earthquake and tsunami, it was originally begun by architect Manuel Caetano de Sousa, who planned a late Baroque-Rococo building. Later, it was entrusted to José da Costa e Silva and Francisco Xavier Fabri, who planned a magnificent building in the modern neoclassical style.

Over time the project has undergone several periods when the construction was stopped or slowed due to financial constraints or political conflicts. When the Royal Family had to flee to Brazil (in 1807), following the invasion of Portugal by French troops, and the work proceeded very slowly with Fabri taking charge of the project, later followed by António Francisco Rosa. Lack of financial resources would also a result in the reduction of the projects scale. The construction of the Ajuda Palace, which began in 1796 and lasted until the 19th century, was a project plagued by various/diverse political, economic and artistic/architectonic problems. It was invaded by Napoleon's troops in 1807, and discontinued by Liberal forces who imposed a constitutional monarchy that reduced the power of the monarchy. Artistically, it was a convergence of the Baroque styles from Mafra, very connected to regal authority, with the birth of the Neoclassic style from Italy. These tastes were affected by successive interruptions, due to a lack of funds, political sanctions or disconnection between the workers and authorities who were responsible for the project. The project was various times modified, but were generally authored by Manuel Caetano de Sousa (the last Baroque architect) and, later, Costa e Silva and Fabri, both Bolognese architects whose tastes crossed the architectural spectrum, but in which Neoclassicism predominated.