The Casa da Junta ("House of the Council"), also known as the Old Legislative Assembly, is a historic building in the Brazilian city of Porto Alegre, the capital of the state of Rio Grande do Sul, located at 1029 Duque de Caxias Street, at the historic center.

It was designed by Captain José Montanha, during the administration of José Marcelino de Figueiredo, and was conceived as a set with the old government palace, on the left, which was demolished to make way for the current Piratini Palace.

Initially built with only one floor, it was remodeled and expanded in 1860, when its old colonial aspect was changed with neoclassical elements.

Between 1937 and 1947, during the Vargas Era, it remained closed once more due to the dissolution of the legislatures, being renovated in 1947 to receive the new deputies of the third state Constituent Assembly.

It continued to host the Assembly until 1967, when the new collegiate building, the Farroupilha ("Ragamuffin") Palace, was inaugurated.