The 1991 Giro d'Italia was the 74th edition of the race. It began on May 26 with a mass-start stage that began and ended in the Italian city of Olbia. The race came to a close in Milan on June 16. Twenty teams entered the race, which was won by the Italian Franco Chioccioli of the Del Tongo-MG Boys Maglificio team. Second and third respectively were the Italians Claudio Chiappucci and Massimiliano Lelli.

The Giro d'Italia is an annual multiple-stage bicycle race primarily held in Italy, while also starting in, or passing through, other countries. The first race was organized in 1909 to increase sales of the newspaper La Gazzetta dello Sport, and the race is still run by a subsidiary of that paper's owner. The race has been held annually since its first edition in 1909, except during the two world wars. As the Giro gained prominence and popularity the race was lengthened, and the peloton expanded from primarily Italian participation to riders from all over the world. The Giro is a UCI World Tour event, which means that the teams that compete in the race are mostly UCI WorldTeams, with some additional teams invited as 'wild cards'.