Wieslaw Stanislaw Ptak (16 September 1941 – 11 April 2004) was a Polish chemist, professor of chemical sciences, professor at the AGH University of Science and Technology in Kraków and Dean of the Faculty of Materials Science and Ceramics at AGH (1993–1996).
Ptak was a member of the Polish Chemical Society and the International Society for Theoretical Chemical Physics (ISTCP).