Warsaw Public Library – Central Library of the Masovian Voivodeship (Polish: Biblioteka Publiczna m.st. Warszawy – Biblioteka Główna Województwa Mazowieckiego) is a public library serving as the main city public library of Warsaw, as well as of the Masovian Voivodeship, and one of the largest in Poland. It is known colloquially as Koszykowa Library (Polish: Biblioteka na Koszykowej) after Koszykowa Street on which it is located.