The 2021 Idemitsu Mazda MX-5 Cup presented by BF Goodrich was a single-make motor racing championship, the 17th season of the Mazda MX-5 Cup and the 1st under a new sanctioning agreement with the International Motor Sports Association (IMSA). The series began on January 28 at Daytona International Speedway, and concluded on November 12 at Michelin Raceway Road Atlanta after 14 rounds. Gresham Wagner won the driver's championship, earning Spark Performance the entrant's championship as well. Sam Paley won the Rookie of the Year championship with McCumbee McAleer Racing.