Giampaolo, 53, took over last August after the Turin side finished last season in 16th position.
But the club are struggling third from bottom of the league with just two wins this campaign and none at home.
Torino owner Urbano Cairo on Saturday blasted "the worst match of the season" after a goalless draw at home against minnows Spezia who played 82 minutes a man down.
"Torino Football club announces that it has sacked Marco Giampaolo from the post of coach of the first team," the team said in a statement on Monday.
"The club thanks Giampaolo and his staff for the professionalism and commitment shown in these months with the Granata."
Giampaolo was also sacked by AC Milan in October 2019 after just seven matches in charge.
Ex-Genoa coach Davide Nicola, 47, was reported to be set to take over at the club he played for in the 2005-2006 Serie B season and helped into the top flight.
Nicola was sacked last August after eight months in charge of Genoa. He previously coached Bari, Crotone and Udinese.
Former Italian footballing giants Torino won the last of their seven league titles in 1976.
This season they have relied heavily on the goals of captain Andrea Belotti who has scored nine of the club's 26 goals in 18 games.