The International Exhibition of 1865, called the "Exposição Internacional do Porto", was a world's fair held in 1865 in the Portuguese city of Porto. The exhibition itself was housed inside the grand Palácio de Cristal which, designed by English architect Thomas Dillen Jones, was modelled on the building of the same name constructed in London for The Great Exhibition in 1851. The exhibition was inaugurated on the 15 September in the presence of the Portuguese king Luís I and his consort Maria Pia of Savoy. It was the first world's fair to be held on the Iberian Peninsula.
It was chiefly organized by the Associação Industrial Portuense (today called the Associação Empresarial de Portugal) and hosted 3,139 exhibitors, of which 499 were French, 265 German, 107 British, 89 Belgian, 62 Brazilian, 24 Spanish, 16 Danish as well as various other representatives from Russia, the Netherlands, Turkey, the United States and Japan.