2018 IMSA SportsCar Championship

The 2018 IMSA SportsCar Championship (known for sponsorship reasons as the 2018 IMSA WeatherTech SportsCar Championship) was the 48th motor racing championship sanctioned by the International Motor Sports Association (IMSA) (which traces its lineage to the 1971 IMSA GT Championship). It was the fifth season of the United SportsCar Championship and third to be held under the name as the IMSA SportsCar Championship. It began on January 27 with the 24 Hours of Daytona, and ended on October 13 with the Petit Le Mans.

The No. 31 Whelen Engineering Racing car won the Prototype Teams and Drivers' Championship, with Cadillac winning the Prototype Manufacturers' Championship. The No. 3 Corvette Racing won the GT Le Mans Teams' and Drivers' Championship, with Chevrolet winning the GT Le Mans Manufacturers' Championship. The No. 48 Paul Miller Racing won the GT Daytona Teams' and Drivers' championship with Lamborghini winning the GT Daytona Manufacturers' Championsip.