Gustavo Marzi (25 November 1908 – 14 November 1966) was an Italian fencer.

He competed in foil and sabre events at the 1928, 1932 and 1936 Olympics and won a gold or silver medal in every event he entered, except for individual sabre in 1928, in which he finished fourth.

In total he won two gold and five silver medals.

[1] At the world championships, which were unofficial through 1935, he won 10 titles: two in the individual foil (1935, 1937), seven in team foil (1929–31, 1934–35, 1937–38) and one in team sabre (1938).

He died from a lung cancer, aged 57.