The 1978 Belgian Grand Prix was a Formula One motor race held on 21 May 1978 at Zolder. It was the sixth race of the 1978 World Championship of F1 Drivers and the 1978 International Cup for F1 Constructors. The 70-lap race was won from pole position by Mario Andretti, driving the new Lotus 79. Teammate Ronnie Peterson was second in the older Lotus 78, with Carlos Reutemann third in a Ferrari.