Leopold Vietoris (4 June 1891 – 9 April 2002) was an Austrian mathematician and a World War I veteran. He was born in Radkersburg and died in Innsbruck. He was known for his contributions to topology — notably the Mayer-Vietoris sequence — and other fields of mathematics, his interest in mathematical history and for being a keen alpinist. Vietoris attended the University of Vienna, where he earned his Ph.D in 1920. Vietoris was survived by his six daughters, 17 grandchildren, and 30 great-grandchildren.