Niels Koolen (; born 25 May 2001) is a Dutch racing driver. He currently competes in the Indy NXT series, driving for Chip Ganassi Racing. Koolen most recently competed in the European Le Mans Series driving for the Duqueine Team. He is the son of rally raid driver and businessman Kees Koolen.
After competing in karting prior to the COVID-19 pandemic, Koolen, a relatively latecomer to single-seater racing aged 21, made his car racing debut in Round 6 of the 2022 F4 Spanish Championship, driving for Monlau Motorsport. He contested the final two rounds of the 2022 Italian F4 Championship, also with Monlau Motorsport, competing under a Belgian license.
On 5 January 2023, it was announced that Koolen would drive for VAR-Pinnacle Motorsport in the 2023 Formula Regional Middle East Championship. He finished 31st in the final standings with no points finishes.
Following the 2022 season, Koolen partook in several Formula Regional European Championship tests, driving for Van Amersfoort Racing. He would ultimately sign with the Dutch-based team to participate in the 2023 championship alongside Joshua Dufek and Kas Haverkort. He struggled and was considerably behind his teammate throughout the whole campaign, and finished the standings 37th, with a best finish of nineteenth.
Koolen would participate in two rounds of Eurocup-3 in 2023 at Jerez and Estoril, failing to score points in either round.
In August 2024, after Taylor Barnard vacated his seat in the Formula 2 Championship, Koolen was drafted by AIX Racing to race for them in the category for the Monza and Baku rounds alongside Joshua Dürksen. He got nineteenth in both the Monza sprint and feature race. After the next weekend in Baku, AIX Racing confirmed that Koolen would not return for the final two weekends of the season.
In 2024, Koolen switched to Indy NXT with HMD Motorsports. In the first race of the Indianapolis Motor Speedway, he finished tenth. This was his best result of the season.
In 2025, Chip Ganassi Racing signed Koolen to run the full season, marking his second season in the category. He finished eighth in the points standings with a best finish of fifth at Iowa Speedway.
Koolen will continue with Chip Ganassi Racing for the 2026 season.
Alongside his Indy NXT season, Koolen made his endurance racing debut and competed in the 2024 European Le Mans Series with the Duqueine Team.
<sup>â </sup> As Koolen was a guest driver, he was ineligible to score points. <nowiki>*</nowiki> Season still in progress.
() (Races in bold indicate pole position) (Races in italics indicate fastest lap)
() (Races in bold indicate pole position) (Races in italics indicate fastest lap)
() (Races in bold indicate pole position) (Races in italics indicate fastest lap)
() (Races in bold indicate pole position) (Races in italics indicate fastest lap)
() (Races in bold indicate pole position) (Races in italics indicate fastest lap)
() (Races in bold indicate pole position) (Races in italics indicate fastest lap)
() (Races in bold indicate pole position; results in italics indicate fastest lap)
() (Races in bold indicate pole position) (Races in italics indicate fastest lap) (Races with <sup>L</sup> indicate a race lap led) (Races with * indicate most race laps led)