Igor Cassina (born August 15, 1977 in Seregno, Province of Milan) is an Italian gymnast who won gold in the men's horizontal bar at the 2004 Summer Olympics in Athens. This competition saw a crowd protest over a low score for a routine by Alexei Nemov of Russia, which lasted for fifteen minutes until the score was raised. Despite this atmosphere, Cassina performed his exercise without major error, and he took the gold medal over Paul Hamm of the U.S., even though they tied. This gold was also the 500th Italian medal at the Summer Olympics. At the 2008 Summer Olympics he was 4th in the man's horizontal bar.
At the World Gymnastics Championships he won in Anaheim 2003 the silver medal and in London 2009 the bronze medal.
At the European Gymnastics Championships he won in Patras 2002 and Debrecen 2005 the silver medal and in Amsterdam 2007 the bronze medal, always in the man's horzontal bar.
Igor Cassina had already entered the history of gymnastics before winning the Olympic gold. He was the first ever to perform a giant Kovacs straight with 1/1 turn (also known as a Kõlman in the straight position), which the International Gymnastics Federation decided to name Cassina after him as from 2002.