"What U Gon' Do" is a single by Lil Jon & the Eastside Boyz from their album Crunk Juice and features Lil Scrappy. It is one of the best known songs that Lil' Jon & The Eastside Boyz recorded together.
The track reached #22 on the Billboard Hot 100, #8 on the Hot Rap Tracks chart, and #13 on the Hot R&B/Hip-Hop Singles & Tracks chart.
Two remixes to the song was an addition to the Crunk Juice in the Remix CD. A Jamaican remix featuring Elephant Man and Lady Saw and a Latino remix featuring Pitbull and Daddy Yankee. The Latino remix became the official remix.
The song appeared in a season one episode of The Andy Milonakis Show when Lil Jon guest starred.