The 2021 NASCAR Whelen Euro Series is the thirteenth Racecar Euro Series season, and the ninth under the NASCAR Whelen Euro Series branding. The season began at Circuit Ricardo Tormo with the NASCAR GP Spain on 15 May and ended on 31 October with the NASCAR GP Italy at Autodromo Vallelunga.
Despite not taking part in the fifth round at Zolder to compete in the NASCAR Xfinity Series race at the Charlotte Roval, Loris Hezemans was crowned as champion at Vallelunga after winning four races and finishing 7 races inside the podium, his second title in the series. He finished the season 3 points ahead of Gianmarco Ercoli, who scored a race win at Rijeka and 7 podium finishes. Lucas Lasserre finished third despite being winless, tying his best championship finish in the series under NASCAR's official sanctioning. Defending series champion Alon Day won three races but was unable to defend his title after retiring four times while defending EuroNASCAR 2 champion Vittorio Ghirelli, who scored his maiden top class victory at Most, had his championship hopes dashed after a crash in the final race of the season. Stienes Longin and Jacques Villeneuve were the other race winners, Longin winning his home race at Zolder while Villeneuve swept the weekend at Vallelunga.
In the EuroNASCAR 2 class, Martin Doubek won the title after teammate Tobias Dauenhauer crashed late in the final round of the season. Both drivers scored a total of five race wins and nine podiums each, but Dauenhauer's incident on the final race handed the championship to Doubek who won the title by 17 points. Not Only Motorsport driver Naveh Talor finished third after scoring his maiden win at Zolder. Indian driver Advait Deodhar was the only other race winner of the season, scoring a victory in the first race at Brands Hatch.
Hendriks Motorsport won the Teams Championship for a record third time as the team's No. 7 car, driven by series champions Hezemans and Doubek, would finish the season on top of the Teams standings with 969 points. DF1 Racing's No. 22 team finished second with 875 points, 94 points adrift from Hendriks' No. 7 team, while the No. 50 Hendriks team would finish third with 867 points.