The Neighbors actor, 26, announced the giveaway in a Twitter photo Monday where he appears posing next to his car with a sign that reads: "Want my first car? It's yours!!!"
The post also included a link to Efron's Make-A-Wish website where he explains his plan to "do something unique and fun to give back."
"I want to give away my first ever car -- and now, you could win a trip to LA to check out the car, take it for a test drive and hang out with me, too! And if you like the car, it's yours to keep," Efron said. "Now all I ask in exchange for your chance to win is for you to help me raise money for one of my favorite charities, Make-A-Wish. Help them change kids' lives with just a small contribution, and you'll be entered to win."
The Make-A-Wish organization grants wishes to children with life-threatening medical conditions.