NASCAR Xfinity Series at Auto Club Speedway

Stock car racing events in the NASCAR Xfinity Series were held at the Auto Club Speedway in Fontana, California from the track's inauguration in 1997 until 2023. The 300-mile (480 km) event was previously named Production Alliance Group 300 for sponsorship reasons most recently in 2023. The race was usually scheduled in late March as the fifth event of the schedule and as a support event for the NASCAR Cup Series' Auto Club 400. It was previously been held in October and late April or early May. John Hunter Nemechek was the last winner of the event, after winning it in 2023.

A second race at the track was also held during the fall as support to the Cup fall race from 2004 until the track lost its second Cup date after 2010.

No races have been held since 2023, as the track is currently undergoing demolition of the 2-mile oval.