The 1909 Giro d'Italia was the 1st edition of the Giro d'Italia, organized and sponsored by the italian major sport newspaper La Gazzetta dello Sport. The event began in Milan on 13 May with a 397 km (247 mi) first stage to Bologna, finishing back in Milan on 30 May after a final stage of 206 km (128 mi) and a total distance covered of 2,447.9 km (1,521 mi). The race was won by the Italian rider Luigi Ganna of the Atala team, with fellow Italians Carlo Galetti and Giovanni Rossignoli coming in second and third respectively.

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'.