The 2018 Auto Club 400 was a Monster Energy NASCAR Cup Series race that was held on March 18, 2018, at Auto Club Speedway in Fontana, California. Contested over 200 laps on the D-shaped oval, it was the fifth race of the 2018 Monster Energy NASCAR Cup Series season.
Auto Club Speedway (previously California Speedway) was a , low-banked, D-shaped oval superspeedway in Fontana, California which hosted NASCAR racing annually from 1997 to 2023. It was also used for open wheel racing events. The racetrack was located near the former locations of Ontario Motor Speedway and Riverside International Raceway. The track was owned and operated by International Speedway Corporation and was the only track owned by ISC to have its naming rights sold. The speedway was served by the nearby Interstate 10 and Interstate 15 freeways as well as a Metrolink station located behind the backstretch.
Kevin Harvick was the fastest in the first practice session with a time of 38.082 seconds and a speed of .
Martin Truex Jr. scored the pole for the race with a time of 38.592 and a speed of .
Kevin Harvick was the fastest in the second practice session with a time of 38.694 seconds and a speed of .
Kyle Busch was the fastest in the final practice session with a time of 38.779 seconds and a speed of .
Stage 1 Laps: 60
Stage 2 Laps: 60
Stage 3 Laps: 80
The race was the 18th race Fox Sports covered at the Auto Club Speedway. Mike Joy, three-time Auto Club winner Jeff Gordon and Darrell Waltrip had call in the booth for the race. Jamie Little, Vince Welch and Matt Yocum handled the pit road duties for the television side.
MRN had the radio call for the race which was also simulcasted on Sirius XM NASCAR Radio. Joe Moore, Jeff Striegle and 2001 race winner Rusty Wallace called the race from the booth when the field was racing down the front stretch. Dan Hubbard called race from a billboard outside turn 2 when the field was racing through turns 1 and 2. Kurt Becker called the race from a billboard outside turn 3 when the field was racing through turns 3 and 4. Alex Hayden, Winston Kelley and Steve Post worked pit road for MRN.