Lü Long (Chinese: 呂隆; died 416), courtesy name Yongji (永基), was the last emperor of the Chinese/Di state Later Liang. He was the nephew of the founding emperor Lü Guang (Emperor Yiwu), and he took the throne after his brother Lü Chao (呂超) assassinated the emperor Lü Zuan (Emperor Ling) in 401 and offered the throne to him. During his reign, Later Liang was under constant attacks by Northern Liang and Southern Liang and reduced largely to its capital Guzang (姑臧, in modern Wuwei, Gansu). In 403, Lü Long decided to end the state by surrendering Guzang to Later Qin's emperor Yao Xing. He became a Later Qin official, but after aligning himself with Yao Xing's son Yao Bi (姚弼), who made unsuccessful attempts to seize the crown prince position from Yao Hong, was executed by Yao Hong after Yao Xing's death in 416.
Not much is known about Lü Long's early life, and his birthdate is not known, and virtually nothing is known about his father Lü Bao. He was described as handsome and skilled at horsemanship and archery. Late in the reign of his uncle Lü Guang (Emperor Yiwu) he served as a general, but he did not have the same prominence that his younger brother Lü Chao (呂超) had.
In 401, Lü Chao assassinated Lü Guang's son Lü Zuan (Emperor Ling) and killed Lü Zuan's brother Lü Wei (呂緯) the Duke of Longxi, and then offered the throne to Lü Long. Initially, Lü Long was hesitant to accept, but Lü Chao compared this to riding a dragon up to heaven and not being able to get off, and Lü Long accepted, using the title "Heavenly Prince" (Tian Wang), roughly equivalent to emperor. He honored his mother Lady Wei as empress dowager, and created his wife Lady Yang as empress. He created Lü Chao the Duke of Anding and entrusted most governmental and military affairs to him.