Glen Johnson vs. Roy Jones Jr. was a professional boxing match contested on September 25, 2004 for the IBF light heavyweight championship.

[1] In his previous fight, then-WBA and WBC Roy Jones Jr. was soundly defeated for the first time in his professional career after being knocked out in the second round of his rematch with Antonio Tarver on May 15, 2004 (his only other loss had been by disqualification in 1997).

Johnson had been a journeyman fighter through most of his professional career and though he had nine losses on his record, he nevertheless was able to land an IBF light heavyweight title match against Clinton Woods.

The two agreed to a match set for December 18, 2004, but both the WBC and IBF refused to sanction the bout as each man was contractually bound to face mandatory challengers, Paul Briggs and Rico Hoye respectively.

[4] For the second straight match, Johnson would pull off an upset victory, defeating Tarver by split decision to become the new The Ring light heavyweight champion.