Li Yu (Chinese: 李煜; c. 937 – 15 August 978), before 961 known as Li Congjia (李從嘉), also known as Li Houzhu (李後主; literally "Last Ruler Li" or "Last Lord Li"), was the third ruler of th Southern Tang state during imperial China's Five Dynasties and Ten Kingdoms period.

Li was interested in cí poetry, which sometimes seems to characterize poetry of the Song Dynasty. However, he is not a Song poet: the Southern Tang is more a successor of Tang and precursor of the Song side that existed during the Tang-Song transition, also known as the Five Dynasties and Ten Kingdoms period. Li Yu represents both a continuation of the Tang poetry tradition, as well as representing the cí poetic style associated with the poetry of Song.