The 2026 NASCAR O'Reilly Auto Parts Series marks the 45th season of the series, running from February 14 at Daytona to November 7 at Homestead-Miami, and debuts a new title sponsor after Xfinity ended its deal. Jesse Love enters as the defending champion, while Justin Allgaier claimed the regular season championship. The grid sees major shakeups, including Kaulig Racing pausing its program, while Sam Hunt Racing, Young's Motorsports, and Jordan Anderson Racing all expand to additional full-time cars. Notable driver moves include Harrison Burton shifting to Sam Hunt Racing, Parker Retzlaff joining Viking Motorsports, and Connor Zilisch moving up to the NASCAR Cup Series. Rookies like Brent Crews (Joe Gibbs Racing), Lavar Scott (Alpha Prime Racing), and Patrick Staropoli (Big Machine Racing) will make their full-time debuts, while teams like Barrett-Cope Racing (a merger) and Peterson Racing (going solo) reshape the competitive landscape.