The reality star posted on Instagram a photo of her friend Jordyn Woods posing in front of a black Mercedes-Benz wrapped in a big red bow.
Kylie wished her friend a happy birthday in the caption, and described Woods as the "most down to earth selfless human being."
"I hope you enjoy it," said Jenner.
Woods, who just turned 18, also posted an Instagram photo of her new ride, thanking Jenner for the generous gift.
"There's no words to describe how I feel...I just don't know what I did to deserve this," said Woods. "I can never thank @kyliejenner for motivating me to always do my best and always opening up new opportunities."