Pietro Grasso (; born 1 January 1945), also known as Piero Grasso, is an Italian anti-mafia magistrate and politician who has been President of the Italian Senate since 16 March 2013. Grasso became Acting President of Italy on 14 January 2015, after the resignation of President Giorgio Napolitano. Sergio Mattarella succeeded Grasso as president when he was elected as the new president of Italy.