Valentí Almirall i Llozer (Catalan pronunciation: [bəɫənˈti əɫmiˈɾaʎ]; Barcelona, Catalonia, Spain, 8 March 1841 – 1904) was a Spanish politician, considered one of the fathers of modern Catalan nationalism, and more specifically, of the left-wing nationalism.
Almirall was a student of the School of Fine Arts in Barcelona but had to leave after criticising the Professor Claudi Lorenzale. In the University of Barcelona, he studied philosophy between 1854 and 1857
Almirall was originally a federal republican who campaigned for the "Catalan Countries" to be united to form an administrative entity as a part of a Spanish Federal Republic. He participated in the Glorious Revolution of 1868. His wealth and the little vocation he had of working as a lawyer pushed him into politics. Participated in the preparation and the facts of the revolution of 1868 in Barcelona, directed the newspaper El Federalista (The Federalist) and collaborated with the Federal-Republican Journal, where he published leaflets quite radicals like Guerra a Madrid! (War with Madrid), Bases para la Constitución federal de la Nación Española y para la del Estado de Cataluña (bases for the federal Constitution of the Spanish Nation and for the Catalan State), Observaciones sobre el modo de plantear la confederación en España (Observations on the way to propose the confederation in Spain). As a republican he declared himself hostile to any kind of agreement with the monarchical and took part in the Tortosa Pact (18 May 1869), signed by representatives of Republican organizations in Catalonia, Valencia, the Balearic Islands and Aragon.