The 17-year-old reality star recorded a short video Wednesday on the photo- and video-sharing app, in which she shows herself eating a Popeyes biscuit and supposedly mumbling to someone in the background.
While many fans speculate that she did mutter the words "I'm high as f---," others claim it's too difficult to actually make out what she is saying.
Based on the earlier videos on her feed, which have been saved and uploaded to an Instagram account called kylizzlesnapchats, the Keeping Up with the Kardashians personality was on an airplane when the clip was recorded.
The post has spurred a slew of online comments from fans.
"I remember the first time I smoked weed," a follower commented.
But other Instagram users reminded that the teen could be on an airplane, therefore – quite literally – "high as f----."
Jenner has been buzzed about online in recent weeks. After months of denial, she finally confirmed Wednesday that her lips are enhanced with temporary lip fillers, in a promo for Sunday's episode of her family reality series.
In April, she became the inspiration behind a wacky hashtag trend, the #KylieJennerLipChallenge, in which young fans began using shot glasses to plump up their mouths to mimic Jenner's look. (Jenner did not endorse this fad.)
She Tweeted on April 21, "I want to encourage people/young girls like me to be YOURSELF & not be afraid to experiment w your look."