Li Changyan (李昌言) (d. 884) was a warlord of the late Chinese dynasty Tang dynasty, who controlled Fengxiang Circuit (鳳翔, headquartered in modern Baoji, Shaanxi) from 881 to 884 as its military governor (jiedushi) after overthrowing his predecessor, the former chancellor Zheng Tian.
It is known that as of 881, when Zheng Tian was serving as the military governor of Fengxiang and the overall commander against the major agrarian rebel Huang Chao—after Huang had captured the imperial capital Chang'an earlier that year and forced then-reigning Emperor Xizong to flee to Chengdu—Li Changyan was serving as the commander of the Fengxiang forces (行軍司馬, Xingjun Sima) and stationed at Xingping (興平, in modern Xianyang, Shaanxi).
Zheng, not wanting to have his forces battle each other, transferred his powers to Li Changyan and headed toward Chengdu to join Emperor Xizong, but on the way also offered to resign.
In 883, Emperor Xizong bestowed on him the honorary chancellor title of Tong Zhongshu Menxia Pingzhangshi (同中書門下平章事).
In order to get Zheng to remove himself, Tian and Chen had Li Changyan submit a petition stating, "The soldiers are being troubled.