The 2021 12 Hours of Sebring (formally known as the 69th Mobil 1 Twelve Hours of Sebring Presented by Advance Auto Parts) was an endurance sports car race held at Sebring International Raceway near Sebring, Florida from 17 to 20 March 2021. It was the second round of both the 2021 WeatherTech SportsCar Championship and the Michelin Endurance Cup. Mazda Motorsports entered as the defending overall winners of the 12-hour event.