The model, who recently celebrated her 16th birthday, posted an Instagram snapshot of herself, showing off a row of gold teeth, at what appears to be a fast food restaurant.
The coverings, which clip on over the wearer's own teeth, are the latest rock'n'roll fashion trend for celebs.
Kylie, the youngest half-sister of Kim Kardashian, has recently proven her fashion credentials by launching a clothing line with her sister Kendall, 17.
The advertising campaign for PacSun features both girls and has been popular with their young fans. Both teens regularly post shots of themselves modelling the PacSun line, which includes dungaree dresses and statement tees.
The sisters also have a jewellery line, Metal Haven, at high-end department store Nordstrom, and while they seem to be following in the footsteps of their entrepreneurial older sisters, they refrained from getting advice from the Kardashian clan when it came to their own line.
"I mean with our clothing line and our jewellery line, we didn't want much input from them, just because we wanted this to be all us," Kendall told Fashionista.
Kendall and Kylie will reportedly be home-schooled this autumn to allow time for them to focus on their burgeoning business empire.
Kylie is reportedly dating film star Jaden Smith, and described him as her "best friend" in a sweet online birthday message earlier this year. Smith's quirky style complements Kylie's rock chick look, and he no doubt approves of her new accessory.