The event, which was held over the weekend of 27–29 August at the Circuit de Spa-Francorchamps, marked the sixty-sixth time the Belgian Grand Prix appeared on the season calendar. It rained throughout the weekend which excited some drivers. Mick Schumacher stated that he was "looking forward to getting onto some rain", while Lando Norris said that he was "hoping for a bit of rain." This Grand Prix was the first to enforce article 12.8.4 of Formula One technical regulations, which stated "devices which are used to fit or remove wheel fasteners may only be powered by compressed air or nitrogen." Wheel guns came with sensors that informed mechanics when the wheel was securely fastened, and the governing body deemed a practice of anticipating this signal unsafe.
Following the 2021 Hungarian Grand Prix one month earlier, Lewis Hamilton led the Drivers' Championship by 8 points from Max Verstappen. Mercedes led the Constructors' Championship by 12 points from Red Bull Racing.
Qualifying took place on 28 August and was delayed due to extreme rainfall. George Russell secured Williams Racing's first front row start since the 2017 Italian Grand Prix, and equalled his career-best start. Verstappen took pole position, with Russell second and Hamilton third. Lando Norris crashed in the third segment of qualifying, but was cleared to race after precautionary checks. Race director Michael Masi later admitted it was a mistake to let the third segment of qualifying start on time. Valtteri Bottas and Lance Stroll each received a five-place grid penalty for causing collisions at the previous round.
The race was due to start at 15:00 CEST on 29 August but was delayed multiple times due to persistent rain. Sergio Pérez crashed on his way to the grid, but was allowed to start after mechanics repaired his car. After over three hours of delays, the race officially commenced from the pit lane, with two laps completed under the safety car.
The race was suspended on the third lap and was not resumed. The race result was taken after the first lap, in compliance with Formula One regulations which required a two-lap countback. Verstappen was declared the race winner, scoring his 16th career F1 win and sixth win of the season. George Russell finished second and Lewis Hamilton third. The remaining points scorers were Daniel Ricciardo, Sebastian Vettel, Pierre Gasly, Esteban Ocon, Charles Leclerc, Nicholas Latifi and Carlos Sainz Jr. With only a single official lap completed, and an official completed distance of 6.880 km (4.275 mi), it is the shortest ever race in the history of the sport, eclipsing the previous records set in terms of kilometres of distance covered at the 1991 Australian Grand Prix and in terms of official lap count at the 1971 German Grand Prix. For the sixth time in Formula One history and for the first time since the 2009 Malaysian Grand Prix, half points were awarded.
The decision to run two laps behind the safety car and then red-flag the race stirred much controversy. The FIA and then race director Michael Masi faced criticism from media, fans, teams and drivers for their decision-making during the weekend, and particularly on race day. Some commentators and competitors questioned the validity and sporting integrity of officially classifying and awarding points when the only laps completed were behind the safety car with no overtaking permitted. Others felt the awarding of half points was justified to reward competitors who had qualified well. The sport subsequently set about finding methods of preventing a repeat scenario, changing the sporting regulations to state a race must involve a minimum of two laps under green flag conditions for points to be awarded. Subsequent changes to point structure for shortened races meant reduced points would be awarded to fewer drivers depending on distance covered. As of 2026, this race holds the record for the shortest Formula One World Championship race in terms of distance and number of laps raced.