The 1978 Brazilian Grand Prix was a Formula One motor race held on 29 January 1978 at Jacarepagua.

The race was run at the height of summer in Rio de Janeiro in 100°F temperatures, and it was won by Argentine driver Carlos Reutemann driving a Ferrari 312T2 in a flag-to-flag performance.

Hunt in the leading McLaren and Andretti in the leading Lotus were running 2nd and 3rd behind Reutemann, until Hunt was forced to pit for tyres whilst Andretti soon started to suffer from gearbox problems and dropped to 4th, handing their 2nd and 3rd places over to home favourite Emerson Fittipaldi and reigning world-champion Niki Lauda respectively.

The hot and humid conditions had eventually caused Hunt, Tambay and Villeneuve in the other Ferrari to all spin off and crash by lap 36.

Reutemann meanwhile had no challengers for the lead all race long, and won by a comfortable margin ahead of former double world-champion Fittipaldi, Lauda, Andretti in the remaining Lotus, Clay Regazzoni in the Shadow and Didier Pironi in the Tyrrell.