Pastrana announced his decision on his Facebook page. He cited a lack of sponsorship, a desire to spend time with his wife and new daughter and frustration over his struggles in NASCAR as his reasons for leaving the sport.
"It's tough to step back now and prove the critics were right, but unfortunately my results were not good enough to get the sponsors I needed to appropriately fund next season," Pastrana wrote. "My wife Lyn-z has been more than supportive of my foray into NASCAR, often times being my biggest source of encouragement and support. But as my wife had to take a step back from being a professional skater to let me chase my goals in racing, I too need to take a step back and look at my situation as a father and husband.
"The NASCAR schedule is grueling and takes enormous sacrifices from those you love to make work," he added. "With a lack of funding next year, now is my opportunity to sit back and offer support as she chases her goals."
The Pastrana's welcomed daughter, Addy, in early September.
One of the most popular action sports stars in the world and a 17-time medal winner at the X Games, Pastrana first tried NASCAR in 2011. He was scheduled to make his Nationwide debut that July, but broke his leg in an X Games accident two days before the race.
He joined Roush-Fenway Racing this season and has four top-10s heading into Saturday's finale. He's 14th in the Nationwide standings and has a 21.4 average finish.
"I hate to quit and I hate to fail, but sometimes things work out as they should," Pastrana wrote. "I've never been able to figure out the finesse required in pavement racing and that is disappointing, but I'm looking forward to driving more rally and racing more off-road trucks and there will be some announcements on those fronts shortly! My wife is excited to get back to skating on the Nitro Circus Live Tour and I'm excited to spend some quality time with my girls."