The reality star, who won a Teen Choice Award this weekend for Choice Snapchatter, stepped out in a curve-hugging Balmain catsuit to celebrate at The Nice Guy in West Hollywood, California, with her famous friends and family on Sunday night. In true Kylie fashion, much of her party was posted to Snapchat, and she made sure her followers got a good look at her skintight style.
All of Kylie's stylish sisters were in attendance, as well as her mother Kris Jenner, boyfriend Tyga, her friend Jordyn Woods, Kourtney Kardashian's ex Scott Disick, R&B singer Chris Brown and his ex Karrueche Tran.
The party included a photo booth that was taken full advantage of by the Keeping Up With the Kardashians stars. Kylie even shared a sloppy kiss with Tyga, and labeled the snap, "My bestie."
Khloe Kardashian made a profanity-laden speech in celebration of her little sister. "I just want to say how proud I am of Kylie," she gushed. "Kylie, you're a f**king rich-a** b**ch, and I f**king love you."
Kylie's birthday cake couldn't have been more perfect, as it was a replica of the mouth logo seen on her wildly successful lip kits.
Kourtney and Kim also made a point to get in on their sister's Snapchat story. "We're the real deal," Kourtney declared in a selfie video with the birthday girl.
Kylie's actual birthday is August 10, and ET chatted with her pal, Jordyn Woods, ahead of all the festivities, and got an inside look into their sweet friendship. "You know, together her and I -- and all of our friends -- we just always build each other up no matter who it is," the model shared. "Whoever I'm around, I just want to see them do their best. So whenever we're all together, we just always motivate each other, and just tell each other how beautiful they are every day."