"You Know What It Is" is the second single off T.I.'s 5th album T.I. vs. T.I.P.. This is a T.I.P. song. The song was written by T.I., produced by Wyclef Jean.

The official retail version of the single was leaked to the internet on June 13, 2007.

It debuted at #73 on Billboard's R&B/Hip Hop Songs on June 28, 2007. Later it debuted on the Billboard Hot 100 at number 68 in July.

The song was featured in HBO's hit series Entourage (Season 4, Episode 4) as the guys are in a club, it can be heard in the background.