The Brazilian monitor Alagoas was the third ship of the Pará-class river monitors built for the Brazilian Navy during the Paraguayan War in the late 1860s. Alagoas participated in the Passagem de Humaitá in February 1868 and provided fire support for the army for the rest of the war. The ship was assigned to the Upper Uruguay () Flotilla after the war. Alagoas was transferred to Rio de Janeiro in the 1890s and participated in the Fleet Revolt of 1893–94. The ship was scrapped in 1900.