"Kryptonite (I'm on It)" is a posse cut song by American Southern hip hop collective Purple Ribbon All-Stars.

It was released on January 6, 2006 via Purple Ribbon/Virgin Records as the lead single from their album Big Boi Presents... Got Purp?

Written and performed by members Big Boi, Killer Mike, BlackOwned C-Bone and Rock D, it was produced by The Beat Bullies.

An official remix was made, which features Big Boi, Killer Mike, Busta Rhymes, Lil' Wayne, Bubba Sparxxx and Remy Ma.

It was covered by rock band Emanuel for 2008 compilation album Punk Goes Crunk.