The Alpine A521 is a Formula One car designed by the Alpine F1 Team which competed in the 2021 Formula One World Championship. It was driven by Fernando Alonso, marking his return to the sport, and Esteban Ocon. It was the first to be fielded under the team's Alpine name.

Alpine F1 Team, or currently BWT Alpine F1 Team for sponsorship reasons, is the name under which the Enstone-based Formula One team has been competing since the start of the 2021 Formula One World Championship. Formerly named Renault F1 Team and owned by the French automotive company Groupe Renault as well as Renault–Nissan–Mitsubishi Alliance, the team was rebranded for 2021 to promote Renault's sports car brand, Alpine, and continues to serve as Renault's works team. The chassis and managerial side of the team is based in Enstone, Oxfordshire, England, and the Renault-branded engine side of the team is based in Viry-Châtillon, a suburb of Paris, France. The team competes with a French licence.