Isadoro Anthony "Izzy" Jannazzo (January 31, 1915 – June 18, 1995) was an American professional boxer who contended for the NYSAC, NBA, and The Ring magazine world welterweight championship against Barney Ross in November 1936, and took the Maryland version of the World Welterweight Championship in October 1940. In 1937, he fought national welterweight champions before large crowds in Australia and Germany. In 1940, he was listed as the world's top welterweight contender by some sources. His managers were Guy Anselmi and Chris Dundee.