Santiago Grassi (born 25 September 1996) is an Argentine swimmer.

He competed at the 2016 Summer Olympics in the men's 100 metre butterfly; his time of 52.56 seconds in the heats did not qualify him for the semifinals.

[1][2] He represented Argentina again at the 2020 Summer Olympics in the men's 100 metre butterfly event.

[3][4] He won the silver medal in the men's 100 metre butterfly event at the 2015 Pan American Games.

This biographical article related to an Argentine swimmer is a stub.