The 2012 Auto Club 400 was a NASCAR Sprint Cup Series stock car race held on March 25 at Auto Club Speedway in Fontana, California. Shortened to 129 laps because of rain showers, it was the fifth race of the 2012 Sprint Cup Series season. The race was won by Tony Stewart for the Stewart-Haas Racing team. Kyle Busch finished second, and Dale Earnhardt Jr., who started fourteenth, clinched third.

Auto Club Speedway was a 2.000 mi (3.219 km), D-shaped oval superspeedway in unincorporated San Bernardino County, California, near Fontana. It hosted National Association for Stock Car Auto Racing (NASCAR) racing annually from 1997 until 2023. It was also previously used for open wheel racing events. The racetrack is located 47 mi (76 km) east of Los Angeles and is near the former locations of Ontario Motor Speedway and Riverside International Raceway. The track is owned and operated by NASCAR. The speedway is served by the nearby Interstates 10 and 15 freeways as well as a Metrolink station located behind the backstretch.