| Type: | F1 |
| Country: | Italy |
| Grand Prix: | Italian |
| Official Name: | XXVI Gran Premio d'Italia |
| Date: | September 11 |
| Year: | 1955 |
| Previous Round: | 1955 British Grand Prix |
| Next Round: | 1956 Argentine Grand Prix |
| Location: | Autodromo Nazionale di Monza, Monza, Italy |
| Course: | Permanent road course |
| Course Mi: | 6.214 |
| Course Km: | 10.000 |
| Distance Laps: | 50 |
| Distance Mi: | 310.700 |
| Distance Km: | 500.023 |
| Pole Driver: | Juan Manuel Fangio |
| Pole Team: | Mercedes |
| Pole Time: | 2:46.5 |
| Pole Country: | Argentina |
| Fast Driver: | Stirling Moss |
| Fast Team: | Mercedes |
| Fast Time: | 2:46.9 |
| Fast Country: | United Kingdom |
| First Driver: | Juan Manuel Fangio |
| First Team: | Mercedes |
| First Country: | Argentina |
| Second Driver: | Piero Taruffi |
| Second Team: | Mercedes |
| Second Country: | Italy |
| Third Driver: | Eugenio Castellotti |
| Third Team: | Ferrari |
| Third Country: | Italy |
The 1955 Italian Grand Prix was a Formula One motor race held at Autodromo Nazionale di Monza, in Monza, Italy on 11 September 1955. It was the seventh and final race of the 1955 World Championship of Drivers.
In the wake of the 1955 Le Mans disaster, the championship was still open after the British Grand Prix; although after that race (with the French Grand Prix already having been cancelled) the German, Swiss and Spanish Grands Prix were all cancelled. This meant that Fangio won the world driver's championship for the 3rd time and the 2nd time in succession.
A new concrete banking had been constructed over where the original slightly banked version was, and the combined 10 km (6.214 mi) Monza circuit was used for the first time since 1933. The Curva Sud had also been modified from 2 right hand corners into one sweeping right-hander known as the "Parabolica".
Of the 4 factory Mercedes cars in the race, Fangio and Moss drove the streamlined, closed-wheel W196's, while Kling and Taruffi drove open-wheel W196's. This was the 4th and last appearance of the streamlined Mercedes cars at a championship GP as well as the third and last time in Formula One history that a race had been won by a closed-wheel car.
This was the last Grand Prix race for 1950 world champion Nino Farina. This was also the last Grand Prix win for a Mercedes-Benz as an engine manufacturer until David Coulthard won the 1997 Australian Grand Prix and the last Grand Prix win for Mercedes-Benz as a constructor until Nico Rosberg won the 2012 Chinese Grand Prix, and also the last 1-2 finish for Mercedes-Benz as an engine manufacturer until Mika Häkkinen and Coulthard at the 1997 European Grand Prix, as well as the last 1-2 finish for Mercedes-Benz as a constructor until Lewis Hamilton and Rosberg at the 2014 Malaysian Grand Prix.
| 1 | 18 |  Juan Manuel Fangio | Mercedes | 2:46.5 | — | |
|---|---|---|---|---|---|---|
| 2 | 16 | Stirling Moss | Mercedes | 2:46.8 | +0.3 | |
| 3 | 20 |  Karl Kling | Mercedes | 2:48.3 | +1.8 | |
| 4 | 4 |  Eugenio Castellotti | Ferrari | 2:49.6 | +3.1 | |
| 5 | 2 | Nino Farina | Lancia | 2:49.9 | +3.4 | |
| 6 | 36 |  Jean Behra | Maserati | 2:50.1 | +3.6 | |
| 7 | 28 | Roberto Mieres | Maserati | 2:51.1 | +4.6 | |
| 8 | 10 | Luigi Villoresi | Lancia | 2:51.6 | +5.1 | |
| 9 | 14 | Piero Taruffi | Mercedes | 2:51.8 | +5.3 | |
| 10 | 30 | Luigi Musso | Maserati | 2:52.1 | +5.6 | |
| 11 | 32 | Peter Collins | Maserati | 2:55.3 | +8.8 | |
| 12 | 12 | Umberto Maglioli | Ferrari | 2:55.4 | +8.9 | |
| 13 | 42 |  Harry Schell | Vanwall | 2:55.5 | +9.0 | |
| 14 | 6 | Mike Hawthorn | Ferrari | 2:56.2 | +9.7 | |
| 15 | 8 | Maurice Trintignant | Ferrari | 2:56.3 | +9.8 | |
| 16 | 34 | Carlos Menditeguy | Maserati | 2:58.4 | +11.9 | |
| 17 | 44 | Ken Wharton | Vanwall | 2:59.5 | +13.0 | |
| 18 | 22 |  Hermano da Silva Ramos | Gordini | 2:59.8 | +13.3 | |
| 19 | 26 | Jacques Pollet | Gordini | 2:59.9 | +13.4 | |
| 20 | 40 | John Fitch | Maserati | 3:03.1 | +16.6 | |
| 21 | 38 | Horace Gould | Maserati | 3:05.2 | +18.7 | |
| 22 | 24 | Jean Lucas | Gordini | 3:15.9 | +29.4 | |
| DNS | 46 | Luigi Piotti | Arzani-Volpini-Maserati | |||
| Source:[1] | ||||||
| Pos | No | Driver | Constructor | Laps | Time/Retired | Grid | Points | |
|---|---|---|---|---|---|---|---|---|
| 1 | 18 | Juan Manuel Fangio | Mercedes | 50 | 2:25:04.4 | 1 | 8 | |
| 2 | 14 | Piero Taruffi | Mercedes | 50 | +0.7 | 9 | 6 | |
| 3 | 4 | Eugenio Castellotti | Ferrari | 50 | +46.2 | 4 | 4 | |
| 4 | 36 | Jean Behra | Maserati | 50 | +3:57.5 | 6 | 3 | |
| 5 | 34 | Carlos Menditeguy | Maserati | 49 | +1 Lap | 16 | 2 | |
| 6 | 12 | Umberto Maglioli | Ferrari | 49 | +1 Lap | 12 | ||
| 7 | 28 | Roberto Mieres | Maserati | 48 | +2 Laps | 7 | ||
| 8 | 8 | Maurice Trintignant | Ferrari | 47 | +3 Laps | 15 | ||
| 9 | 40 | John Fitch | Maserati | 46 | +4 Laps | 20 | ||
| 10 | 6 | Mike Hawthorn | Ferrari | 38 | Gearbox | 14 | ||
| Ret | 20 | Karl Kling | Mercedes | 32 | Gearbox | 3 | ||
| Ret | 30 | Luigi Musso | Maserati | 31 | Gearbox | 10 | ||
| Ret | 38 | Horace Gould | Maserati | 31 | Suspension | 21 | ||
| Ret | 16 | Stirling Moss | Mercedes | 27 | Engine | 2 | 1 | |
| Ret | 26 | Jacques Pollet | Gordini | 26 | Engine | 19 | ||
| Ret | 22 | Hermano da Silva Ramos | Gordini | 23 | Fuel System | 18 | ||
| Ret | 32 | Peter Collins | Maserati | 22 | Suspension | 11 | ||
| Ret | 42 | Harry Schell | Vanwall | 7 | Suspension | 13 | ||
| Ret | 24 | Jean Lucas | Gordini | 7 | Engine | 22 | ||
| Ret | 44 | Ken Wharton | Vanwall | 0 | Injection | 17 | ||
| DNS | 2 | Nino Farina | Lancia | Tyre | 5 | |||
| DNS | 10 | Luigi Villoresi | Lancia | Tyre | 8 | |||
| DNS | 46 | Luigi Piotti | Arzani-Volpini-Maserati | Engine | ||||
| Pos | Driver | Points | ||
|---|---|---|---|---|
| 1 | Juan Manuel Fangio | 40 (41) | ||
| 2 | 23 | |||
| 3 | 3 | Eugenio Castellotti | 12 | |
| 1 | 4 | Maurice Trintignant | 11 | |
| 1 | 5 | Nino Farina | 10 | |
| Source: [2] | ||||