|Born||27 March 1867
Vienna, Austro-Hungarian Empire
|Died||14 October 1925
|Nationality||Austro-Hungarian Empire, Austria|
|Institutions||University of Vienna|
|Alma mater||University of Vienna|
|Known for||Zsigmondy's theorem|
Karl Zsigmondy (Hungarian pronunciation: [ˈʒiɡmondi]) (27 March 1867 – 14 October 1925) was an Austrian mathematician of Hungarian ethnicity. He was a son of Adolf Zsigmondy from Pozsony, Kingdom of Hungary (now Bratislava, Slovakia) and his mother was Irma von Szakmáry of Martonvásár, Kingdom of Hungary.
He studied (1886–1890) and worked (1894–1925) at the University of Vienna. After his PhD, in 1890, he studied at the University of Berlin, University of Göttingen and at the Sorbonne in Paris, but came back to Vienna in 1894. He discovered Zsigmondy's theorem in 1882.
- K. Zsigmondy (1892). "Zur Theorie der Potenzreste". Journal Monatshefte für Mathematik. 3 (1): 265–284. doi:10.1007/BF01692444.
- Th. Schmid (1927). "Karl Zsigmondy". Jahresbericht der Deutschen Mathematiker-Vereinigung. 36: 167–168.