Eugen Mack (21 September 1907 – 29 October 1978) was a Swiss gymnast and Olympic Champion. He competed at the 1928 and 1936 Summer Olympics, winning a total of two Olympic gold medals, four silver medals and two bronze medals. Although Eugen Mack never won the most coveted individual medal in the sport, that of Olympic All-Around Gold, he did become World All-Around Champion, and with 15 individual medals at the World Championships and Olympics, more than any other gymnast - male or female - in the pre-WWII era and pre-1952 era, he is arguably the most decorated gymnast during this long era.