The 31-year-old posted a picture of the weapon on her Twitter and Instagram accounts today, writing the words 'Bang bang' underneath the photograph, reported Daily Mail online.
Her post set off a flurry of comments from her followers.
"A YSL gun? Great for us chicks that love high fashion."
Other comments were critical, "Oh that is setting a great example to the millions of teens around the world following you."
It wasn't clear from her post whether the gun, which has been popping up on a handful of pop-culture sites is a real gun or just a fashion accessory.
Kim likely got her taste for guns about four years ago, during the second season of 'Keeping Up With the Kardashians'.
This was when mother Kris Jenner took her daughters Kim, Kourtney and Khloe to a shooting range.
The sisters learned how to fire a pistol after the family's store was vandalised, but said at the time they weren't keen to use the weapons in a real-life setting.