"What Hurts the Most" is a country music song written by Jeffrey Steele and Steve Robson. It was originally recorded by American country music singer Mark Wills on his 2003 album And the Crowd Goes Wild. It was to be released as a single, but he was dropped from his label before the song could be released. Nonetheless, Mark's version reached #51 on the Hot Digital Songs chart in 2006. It was also included on Wills' The Definitive Collection compilation album.

The song also appeared on Jeffrey Steele's album You Gotta Start Somewhere in the same year. In 2004, Bellefire, a pop group, recorded the song.