Libero Grassi (; July 19, 1924 – August 29, 1991) was an Italian clothing manufacturer from Palermo, Sicily, who was killed by the Mafia after taking a solitary stand against their extortion demands. The businessman wrote an open letter to the local newspaper informing the extortionists that he was no longer willing to pay "pizzo", a Sicilian term for protection money. Other business-owners and shopkeepers in Palermo refused to join his public campaign. Grassi was gunned down in the street near his home eight months after writing the letter.