Niccolò Sagundino (1402 – March 1464) was a Greek-born Venetian secretary, diplomat and humanist. He wrote numerous letters, as well as religious and philosophical treatises, mostly in Latin. Originally from Euboea, he was in Venetian service when he was wounded and captured by the Ottomans at the fall of Thessaloniki in 1430. He favoured the union between the Catholic and Orthodox churches and worked for the Papacy. He undertook several Venetian missions to the Ottoman court and to Greek lands, on one of which he suffered a shipwreck that killed several of his immediate family. He died in Venice.