Wojciech Alojzy Świętosławski (Polish pronunciation: [ˈvɔjt͡ɕɛx ɕfjɛntɔˈswafskʲi]; 1881–1968) was a Polish physical chemist, who is considered the "father of modern thermochemistry". He developed a static method of cryometric measurement and a new method of testing coal. Świętosławski was vice-chairman of the International Union of Pure and Applied Chemistry (IUPAC) and created the foundations for a new branch of physical chemistry: polyazeotropy. In 1933 he became a member of the Temporary Advisory and Scientific Committee.