The 1965 Belgian Grand Prix was a Formula One motor race held at Spa-Francorchamps on 13 June 1965. It was race 3 of 10 in both the 1965 World Championship of Drivers and the 1965 International Cup for Formula One Manufacturers. The race was won by British driver Jim Clark who led every lap of the race driving a Lotus 33. It was one of the Scot's most dominant wins. In the rain, he pulled away and with a third of the race to go, the Lotus driver was leading his fellow Scotsman Jackie Stewart by 1 minute and 20 seconds. However, for the last six laps Clark eased off dramatically and when the chequered flag was waved his lead was down to just under 45 seconds.

The 1965 Formula One season was the 19th season of FIA Formula One racing. It featured the 16th World Championship of Drivers, the 8th International Cup for F1 Manufacturers, and seven non-championship races open to Formula One cars. The World Championship was contested over ten races between 1 January and 24 October 1965.