Carlo Visconti (died 2 January 1477) was a government secretary in Milan's Council of Justice, one third of the group of that assassinated Galeazzo Maria Sforza, and a member of the Templar Order. He was related to the Visconti who had ruled Milan before it briefly became a republic in 1447 and was finally taken over by Galeazzo's father Francesco in 1450.
On 26 December 1476, Visconti and his fellow Templar brethren Giovanni Andrea Lampugnani, Lampugnani's servant Franzone, and Gerolamo Olgiati, attended the Saint Stephen's Day Mass at the Basilica di Santo Stefano Maggiore. After Lampugnani had delivered the first blow to Sforza after the latter's arrival, the others followed him with their attacks.
While Lampugnani was killed shortly after by one of Sforza's guards, Visconti, Olgiati, and Franzone managed to escape, only to be caught and executed within the next week after Franzone was captured and disclosed the identities of the other two while under torture.