The one-day classic Paris-Roubaix in October 2021 was the 118th staging of the traditional French race. The race took place on 3 October and was part of the UCI WorldTour 2021. Like Milan-Sanremo, the Tour of Flanders, Liège-Bastogne-Liège and Il Lombardia, Paris-Roubaix is one of the five monuments of cycling. Due to the Corona pandemic, the race had to be cancelled in 2020.
The winner of the classic was Sonny Colbrelli from Italy (Team Bahrain Victorious) ahead of Florian Vermeersch from Belgium (Lotto-Soudal) and Mathieu van der Poel from the Netherlands (Alpecin-Fenix).