Janusz Tazbir (August 5, 1927 – May 3, 2016[1]) was a Polish historian, specializing in the culture and religion of Poland in the 16th and 17th centuries.

One of his most famous publications is Państwo bez stosów (A country without stakes) published in 1967.

He was editor-in-chief of the annual academic journal Odrodzenie i reformacja w Polsce (The Renaissance and Reformation in Poland) since 1965, and professor of the Polish Academy of Sciences Institute of History since 1966 (he was the director of the institute from 1983 to 1990).

He was a full professor since 1973 and a member of Polish Academy of Sciences (Polska Akademia Nauk) since 1989.

He was also the leader of the Science Council of Polski Słownik Biograficzny (Polish Biographical Dictionary).