Franciszek Siarczyński (1758–1829) was a Polish Roman Catholic priest, member of the Piarist religious order, historian, geographer, teacher, writer and publicist. He was a lecturer of grammar, history and geography at the Collegium Nobilium in Warsaw, Poland from 1781 to 1785.He was a regular guest at the Thursday Dinners held by the King of Poland, Stanisław August Poniatowski in the era of the Enlightenment in Poland. He was the author of three volumes of ‘Geografii, czyli opisania naturalnego, historycznego i politycznego krajów i narodów’ (Geography, natural history, history and politics of the country and its citizens).