Horacio Bernardo Guillermo Iglesias (April 29, 1942 – June 25, 2004) was an Argentine swimmer who won five world titles in professional marathon swimming (1967, 1969 and 1971–1973). Between 1965 and 1975 he won 28 professional races throughout South America, the United States, Canada and Italy, and was ranked first or second each year. He was inducted as an honoree in the International Swimming Hall of Fame in 2003.