"A Portuguesa" is the national anthem of Portugal. The song was composed by Alfredo Keil and written by Henrique Lopes de Mendonça during the resurgent nationalist movement ignited by the 1890 British Ultimatum to Portugal concerning its African colonies. Used as the marching song of the failed republican rebellion of January 1891, in Porto, it was adopted as the national anthem of the newborn Portuguese Republic in 1911, replacing "Hino da Carta", the anthem of the deposed constitutional monarchy.

The First Portuguese Republic spans a complex 16-year period in the history of Portugal, between the end of the period of constitutional monarchy marked by the 5 October 1910 revolution and the 28 May 1926 coup d'état. The latter movement instituted a military dictatorship known as Ditadura Nacional that would be followed by the corporatist Estado Novo regime of António de Oliveira Salazar.