2015 NASCAR Sprint Cup Series (Start Your Engines!)

The 2015 NASCAR Sprint Cup Series was the 67th season of professional stock car racing in the United States and the 44th modern-era Cup series season.

The season marked the first season of a new television contract. During the season, races were televised in the United States on Fox, Fox Sports 1, NBC, NBCSN, and CBS. ESPN and Turner Sports, who televised races from 2007 to 2014, did not seek to renew their contracts with NASCAR following the completion of the 2014 season, though ESPN did renew the separate contract for the midweek races; this marked the end of a 31-year relationship between NASCAR and Turner's primary stations, TBS and TNT. In addition, it was the first season on the newly rebranded Fox Sports Racing in Canada and the Caribbean.

On January 22, 2015, Jeff Gordon announced that 2015 would be his final season as a full-time driver, but he did not rule out complete retirement. Chase Elliott replaced him in the No. 22 car for Bill Davis Racing in 2016.

2015 saw the entry of Honda into NASCAR, as well as the return of Pontiac factory support for the first time since 2003; Kennedy Racing continued fielding Pontiacs until 2012.

Technical changes
2015 saw the replacement of the SC-13 body with the SC-15 body. Major changes from the SC-13 were to the front nose, which was slimmed considerably for better aero efficiency.

In terms of manufacturers, 2015 saw the number go from four to six. After years of speculation, Honda announced it would be throwing its hat into the NASCAR ring with the Accord. In a surprise announcement the day after the 2014 Los Angeles Times 500, Pontiac announced it would be returning to NASCAR full-time in 2015 with the G8.

Pre-season

 * At road courses, it is now permissible to run qualifying and race sessions under wet-weather conditions. Goodyear will supply wet-weather tires for use in Sprint Cup competition and teams will be required to bring cars with windshield wipers, defoggers, and wet-weather racing capabilities.
 * Flat valve lifters will be replaced with roller valve lifters.
 * Rear spoiler height will be reduced from 8 inches to 6 inches.
 * Teams will have the option of installing a driver adjustable track bar.
 * The radiator pan will be decreased from 43 inches to 38 inches.
 * The minimum weight of the car has been reduced by 50 lb to 3,250 lb.
 * NASCAR has approved a new brake caliper system for 2015 and issued a new parts approval process.
 * Teams are not allowed to alter the side skirts of their cars during the race. At tracks where aerodynamics were important in 2014, many teams would pull the side bodywork of the car during early pit stops. The practice, officially known as vertical rocker panel extensions, was used to limit airflow underneath the vehicle.
 * An automated electronic pit road officiating system will be implemented after extensive testing during the 2014 season, eliminating the need for human officials to stand in the pit lane.
 * If a vehicle has to pit outside its assigned pit box and the crew starts removing tire(s), the team can reinstall the tire(s) before moving the car back into its assigned pit stall to avoid penalties.
 * Additional crew member(s) assisting from an adjacent pit box may be counted towards the limit of seven over the wall.
 * Crew member interference with other teams' pit stops may lead to a penalty.
 * Rules with refueling have been clarified. Refueling can begin once the car comes to a complete stop and can continue when it starts leaving provided equipment and/or the fueler does not leave the pit box. Further, no equipment may be tossed or thrown over the wall at any time.
 * Weight ballasts must be in block form with a five-pound minimum for each block.
 * NASCAR no longer will penalize or monitor missing lug nuts during pit stops, leaving the teams to self-police lug nuts.
 * NASCAR will use an electronic data log and capture system to increase efficiency of pre-race inspections.

In-season changes

 * Starting at Watkins Glen, teams have the option of using a digital dashboard. The dashboards will be heavily regulated by NASCAR as to what can and cannot be displayed. The first team to use the digital dashboard was Kurt Busch at Darlington. The digital dashboards will be mandated in 2016.
 * Starting at the fall Richmond race, NASCAR began to closely review restarts due to drivers jumping the restart.