The 2015 Italian Grand Prix was a Formula One motor race held on 6 September 2015 at the Autodromo Nazionale di Monza in Monza. The race was the twelfth round of the 2015 season.

Hamilton completed the second grand slam of his career by winning the race, taking pole position, setting the fastest lap and leading every lap of the race. He finished 25 seconds ahead of Vettel, while Felipe Massa finished third for Williams. Rosberg retired with three laps to go due to an engine failure, resulting in Hamilton extending his lead in the Drivers' Championship to 53 points. Hamilton's victory was confirmed a few hours after the race following an investigation from race stewards after it was discovered that the left-rear tyre on his Mercedes was below Pirelli's recommended minimum tyre pressure standards in a random check but due to procedural inconsistencies, no sanctions were imposed against either Mercedes driver or the team.