2015 Italian Grand Prix

The 2015 Italian Grand Prix (formally known as the Formula 1 Gran Premio d'Italia 2015) was a Formula One motor race held on 6 September 2015 at the Autodromo Nazionale di Monza in Monza, Italy. The race was the twelfth round of the 2015 season, and marked the 85th running of the Italian Grand Prix.

Lewis Hamilton of Mercedes was the defending race winner, and entered with a 28-point lead over teammate Nico Rosberg in the Drivers' Championship, with Sebastian Vettel a further 39 points behind. Mercedes lead the Constructors' Championship by 184 points over Ferrari, with Williams a further 81 points behind in third.

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.

This race marked the 41st and final podium finish for 2008 World Championship runner-up Felipe Massa and, as of 2025, the most recent podium achieved for a Brazilian driver in Formula One.

Tyre supplier Pirelli brought its white-banded medium compound tyre as the harder "prime" tyre and the yellow-banded soft compound as the softer "option" compound, as opposed to the previous year where the company brought the hard compound as the prime and medium compound as the option. Sauber's Head of Track Engineering, Giampaolo Dallara, praised the updated choice, summing up that it will challenge teams to make time in the corners in addition to going for pure top speed, putting on a better show for the fans. However, Pirelli had received criticism from several drivers and commentators following tyre failures on Nico Rosberg's and Sebastian Vettel's cars at the Belgian Grand Prix. Prior to the Italian Grand Prix, Formula One commercial rights holder Bernie Ecclestone called for the drivers to keep their concerns to themselves, saying: "We're not going to let them [Pirelli] go. They're doing a good job."

The Lotus team, who had their cars impounded by bailiffs following Belgium two weeks earlier, managed to get their cars back in time for the Grand Prix. Despite their financial troubles, the team said it had enough funds for the rest of the season. Meanwhile, contract negotiations were high in the agenda prior to the weekend, with Williams announcing that the team would retain Felipe Massa and Valtteri Bottas for 2016, while Nico Hülkenberg signed a new two-year deal with Force India. An additional talking point was the future of the Italian Grand Prix at Monza, with the event at risk to be dropped from the calendar. After the race, Ferrari driver Sebastian Vettel spoke out in favour of the venue, saying: "If we take this race away from the calendar for any shitty money reasons, you are basically ripping our hearts out".

In terms of technical developments, Ferrari upgraded their engine for their home race by using three of their development tokens while Mercedes spent all seven of their remaining engine tokens. As a result of this, Mercedes became the first team in 2015 to use all their tokens, with both Honda and Ferrari having four tokens remaining and Renault having twelve tokens left for later in the season. Because of these changes both Mercedes cars were on their third powerplants, whilst both Ferrari cars were on their fourth power units. Additionally, Toro Rosso, Red Bull and McLaren received grid penalties for exceeding their parts usage, forcing them to start at the back of the grid. McLaren went back to using their snub nose design, which they had replaced earlier in the season ahead of the Austrian Grand Prix, in order to achieve better aerodynamics and lower drag for the high-speed Monza circuit.

Prior to the race, Lewis Hamilton was leading the World Championship on 227 points, 28 clear of teammate Rosberg. Sebastian Vettel was in third place, another 39 points adrift. In the Constructors' standings, Mercedes were in front on 426 points, with Ferrari and Williams second and third on 242 and 161 points respectively.