Li Yiyan (李義琰) (died 688) was an official of the Chinese Tang dynasty, serving as a chancellor during the reign of Emperor Gaozong.
His family was from Wei Prefecture (魏州, part of modern Handan, Hebei), but his ancestors were said to be originally from Longxi (隴西, in modern Tianshui, Gansu), thus sharing an origin with Tang dynasty's imperial Li clan, but he was considered sufficiently distant not to be considered an imperial clan member.
Li Yiyan himself passed the imperial examinations when he was young, and subsequently served as the sheriff of Taiyuan County.
In 675, when Emperor Gaozong, because of his chronic illness (which might have been hypertension), considered making his powerful wife Empress Wu (later known as Wu Zetian) regent plenipotentiary, the chancellor Hao Chujun vehemently opposed, and Li concurred with Hao, eventually leading to Emperor Gaozong abandoning the idea.
As Li was about to retire to the vicinity of the eastern capital Luoyang, many officials held a feast in his honor just outside the city gates, and this scene was compared to the grand sendoff that was held for the Han dynasty officials Shu Guang (疏廣) and his nephew Shu Shou (疏受), who retired at the height of their careers.
Early on Emperor Ruizong's Chuigong era (685-689), a recall of Li Yiyan was made, asking him to serve as the prefect of Huai Prefecture (懷州, roughly modern Jiaozuo, Henan), but Li, knowing that he had previously offended Empress Dowager Wu by opposing her regency, was apprehensive and did not accept the recall.