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NASCAR’s three national touring series share many tracks, teams and stars, but they are not interchangeable. In 2026 the national ladder is the NASCAR Cup Series, the NASCAR O’Reilly Auto Parts Series and the NASCAR Craftsman Truck Series. If the middle name sounds new, that is because the former Xfinity Series was renamed the O’Reilly Auto Parts Series beginning with the 2026 season.
This comparison focuses on what a fan actually needs to know: where each series sits in NASCAR’s national structure, what kind of vehicles it uses, how long the season is, where to watch, and why drivers sometimes appear in more than one series.
NASCAR Cup Series: the top national level
The NASCAR Cup Series is the organization’s premier national championship. It is where NASCAR’s highest-profile teams and full-time stars compete for the sport’s top title. The Cup schedule is the broadest national showcase, spanning superspeedways, intermediate ovals, short tracks and road or street-course events.
For most casual fans, “NASCAR” on a major Sunday broadcast usually means the Cup Series. In 2026, the late-season NBC/USA portion culminates with the NASCAR Championship at Homestead-Miami Speedway on November 8.
O’Reilly Auto Parts Series: the former Xfinity Series
The NASCAR O’Reilly Auto Parts Series is the national series that was known as the Xfinity Series through 2025. NASCAR’s official 2026 scheduling materials identify it as the newly named O’Reilly Auto Parts Series and list a 33-race season.
It functions as a major development and proving-ground level while also featuring experienced veterans and occasional Cup drivers. Because many organizations operate across multiple NASCAR divisions, the series can be a place to see future Cup regulars before they become household names.
All 2026 O’Reilly Auto Parts Series races are carried by The CW, giving the series a consistent national television home.
Craftsman Truck Series: national racing in pickup-bodied machines
The NASCAR Craftsman Truck Series is the third national series in this comparison and uses purpose-built race trucks with pickup-style bodies. NASCAR’s 2026 schedule contains 25 Truck Series races, fewer than the O’Reilly Auto Parts Series slate.
The Truck Series has its own full-time contenders, teams and championship while also serving as an important development route. Cup and O’Reilly drivers can appear in selected Truck events, but those crossover appearances do not make the Truck Series a secondary event inside a Cup race. It is a separate championship with its own points and season.
Why do Cup drivers race in the other series?
Driver crossover is part of NASCAR’s ecosystem. A Cup regular may enter an O’Reilly or Truck race for additional track time, to race for a team in another division, to help develop equipment, or simply because the event fits the driver’s program. NASCAR applies eligibility and participation rules that can change, so a driver’s appearance in one race should not be treated as proof that the driver is competing for that series championship.
That distinction matters when reading entry lists. NASCAR’s official 2026 Truck and O’Reilly entry lists routinely identify Cup regulars entered in individual events while preserving the separate championship identity of each series.
Do all three series race at the same tracks?
No. The schedules overlap heavily, especially on major NASCAR weekends, but they are not identical. Some tracks host all three national series, some host only one or two, and the 2026 Truck schedule includes its own distinctive events. NASCAR’s official 2026 announcement lists 33 O’Reilly races and 25 Truck races, while the Cup Series follows its own championship calendar.
Which series should a new fan watch first?
If you want NASCAR’s biggest championship and most recognizable stars, start with Cup. If you want to track prospects moving toward Cup while still watching a full national championship, the O’Reilly Auto Parts Series is a strong second lane. If you like shorter national schedules, distinctive truck-shaped race vehicles and a mix of developing talent and established names, add the Craftsman Truck Series.
The best approach is not to treat one as “real NASCAR” and the others as filler. Each is a national series with its own championship, while together they form a connected talent, team and fan ecosystem.
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The short version
In 2026, Cup is NASCAR’s premier national series. The O’Reilly Auto Parts Series is the renamed former Xfinity Series and runs a 33-race schedule. The Craftsman Truck Series races pickup-bodied machines across a 25-race schedule. Drivers and teams can cross between divisions, but each series has its own championship, identity and competitive field.
Source and freshness: Naming, schedules and broadcast details were checked against NASCAR’s official 2026 national-series schedule and current NASCAR entry-list materials. Series sponsorship names, TV homes and participation rules can change, so reverify annually.
Featured image: Casey Calhoun via Unsplash. The photograph is generic stock-car racing imagery and is not presented as a specific NASCAR race or series event.