Roger De Coster (born 28 August 1944) is a Belgian former professional motocross racer and current Motorsport Director of KTM and Husqvarna North America.

De Coster scored a record 36 500cc Grand Prix victories during his racing career, making his name is almost synonymous with the sport of motocross during the 1970s.

[1][4] De Coster was impressed by the meticulous bike preparation and efficient riding styles of Swedish riders such as world champion Torsten Hallman, observing how Hallman absorbed jumps with his body so that his motorcycle flew at half the height of his competitors which, allowed the rear tire to begin applying power to the ground sooner.

His training regime gave him the stamina that allowed him to circulate for most of the race in mid-pack before putting in a late charge through the field to victory when other racers had begun to tire.

[1] De Coster's performances earned him full sponsorship from the factory for the 1967 season in which, he ended year ranked fifth in the 500cc world championship.

[4][8] After the 1967 World Championship season, De Coster joined his ČZ factory teammates Joël Robert and Dave Bickers, along with Husqvarna teammates, Torsten Hallman, Arne Kring and Åke Jonsson, in a series of exhibition races in the United States that had been organized by Edison Dye, the American importer for Husqvarna motorcycles.

[10][11] In 1968, De Coster won his first overall victory with a win at the 500cc Italian Grand Prix, and once again ended the season ranked fifth in the world championship.

[15] Suzuki teammates Robert and Geboers finished first and second in the 250cc world championship with De Coster coming in third place, just 1 point ahead of Mikkola.

[17] His main competition in 1971 came from Paul Friedrichs riding for ČZ and Bengt Åberg on a Husqvarna and the Maico team of Åke Jonsson and Adolf Weil.

[18] While leading the race, the spark plug on Jonnson's motorcycle came loose, allowing DeCoster to pass him for the victory and the 1971 World Championship.

[17][20] De Coster's defense of the 500cc world championship was dealt a setback when, the FIM announced a new motorcycle minimum weight limit of 209 pounds just before the start of the 1973 season.

[21][17][22] Their frustration at their perceived unfair treatment led to a lapse in support and, Suzuki team riders De Coster and Sylvain Geboers then took matters into their own hands by modifying their motorcycle's frames and developed new rear suspension.

[17][21] Going into the final race of the season at Sint Anthonis, Holland, Maico's Willy Bauer was holding the championship points lead.

[25][26] Mikkola missed the German Grand Prix due to injuries suffered in practice, allowing De Coster to narrow Mikkola's lead in the championship to 10 points going into the final two events of the season, meaning that De Coster would have to win three of the last four motos to secure his fourth consecutive 500cc world championship.

[24] The setting of the Belgian Grand Prix was a rugged, narrow track in the forests surrounding the picturesque hilltop Citadel of Namur.

[24] De Coster continued to widen his lead to win the second moto to extend the championship points battle to the final race of the season in Luxembourg.

[33] De Coster's rival Mikkola returned to the 500cc class for the 1977 FIM Motocross World Championship season, this time as a Yamaha factory team rider.

[17] Because of his preseason injuries, De Coster had lost time developing his Suzuki race bike, and he planned to use the fall of 1978 to test new motorcycles and prepare himself for the 1979 season.

[3] De Coster convinced Honda to send an underdog team of Donnie Hansen, Danny LaPorte, Johnny O'Mara and Chuck Sun to compete in the Motocross des Nations.

[3] De Coster rejoined Suzuki as their motocross team manager in 1999 and helped turn around a program that had been in decline since his departure.

In August 2018, De Coster was promoted to official Motorsport Director of KTM and Husqvarna North America, responsible for all racing efforts of both brands in the United States.