The 1984 Italian Grand Prix was a Formula One motor race held at Monza on 9 September 1984. It was the fourteenth round of the 1984 Formula One season.
Niki Lauda won in his McLaren-TAG, stretching his championship lead over team mate Alain Prost (whose TAG engine blew on lap 3) to 10.5 points. Michele Alboreto and Riccardo Patrese gave the partisan Italian crowd something to cheer by bringing their Ferrari and Alfa Romeo home in second and third place respectively.
Sweden's Stefan Johansson finished fourth in his Toleman-Hart (after being last at the end of the first lap), while Austrians Jo Gartner (Osella-Alfa Romeo) and Gerhard Berger (ATS-BMW) finished 5th and 6th respectively, though as their teams had only entered one car for the season and both were in second cars entered for the race, neither Gartner or Berger scored championship points.
Patrese's third place was the final ever Formula One podium for Alfa Romeo as either a constructor or engine supplier, although the position came at the expense of his team mate Eddie Cheever who had been third until his Alfa (which was running a different, more powerful engine setting) ran out of fuel. The 1984 Italian Grand Prix was the only Formula One race in history to have three Austrian drivers finish in the top six placings.
Before the race, Lotus driver Elio de Angelis was the only driver mathematically capable of taking the Drivers' Championship from Lauda or Prost. His chances of becoming the first Italian World Champion since Alberto Ascari in 1953 evaporated when the gearbox in his Lotus-Renault broke on lap 14 leaving him, like Prost, as a non-finisher.
Ayrton Senna did not compete at this Grand Prix. After it was announced at the Dutch Grand Prix that the Brazilian would be joining Lotus in 1985, Toleman suspended him for a breach of contract (i.e. not informing the team he was leaving before the announcement was made which he was required to do as per his contract) and replaced him with Stefan Johansson who went on to finish 4th.