Józef Wierusz-Kowalski (16 March 1866 – 30 November 1927) was a Polish physicist and diplomat. He discovered the phenomenon of progressive phosphorescence. He served as Rector of the University of Fribourg, and helped to establish the section for physics at the reopened University of Warsaw. After Polish independence was established, he served as the Polish ambassador to the Holy See, the Netherlands, Austria and Turkey.