Zhang Jun (張濬) (died January 20, 904), courtesy name Yuchuan (禹川), was an official of the Chinese dynasty Tang Dynasty, serving as a chancellor during the reigns of Emperor Xizong and Emperor Xizong's brother Emperor Zhaozong. Early in Emperor Zhaozong's reign, Zhang was a major advocate for the imperial campaign to regain power from the regional warlords, but was removed after commanding a disastrous campaign against Li Keyong and forced into retirement. Late in Emperor Zhaozong's reign, with Emperor Zhaozong physically controlled by another warlord, Zhu Quanzhong, who had designs on taking over the throne as emperor (and eventually did, founding Later Liang), Zhu, while formerly an ally of Zhang's, was concerned that Zhang would encourage other warlords into a coordinated campaign agains