Lan Han (Chinese: 蘭汗; died August 15, 398) was an official and a consort kin of the Xianbei-led Chinese Later Yan dynasty, who killed the emperor Murong Bao (Emperor Huimin) in 398 and briefly usurped the throne before being killed by Murong Bao's son Murong Sheng (Emperor Zhaowu).
As of 395 Lan Han was referred to as the Prince of Yangcheng and was defending Jicheng (modern Beijing).
In spring 398, after a rebellion by the general Duan Sugu (段速骨) had Murong Bao sieged behind the walls of Longcheng (龍城, in modern Jinzhou, Liaoning), Lan Han was described as having the title of Prince of Dunqiu and commanding an army near the city, but secretly aligned with Duan.
Murong Sheng, who had been suspicious of his father-in-law's intentions and therefore did not join his father's procession back to Longcheng, now decided to arrive at Longcheng to mourn his father, judging correctly that Lan Han would not kill him both because he was Lan's son-in-law and because he pitied Murong Sheng for the destruction of his clan.
As Murong Sheng arrived at Longcheng, his wife Princess Lan further bowed not only to her father but her brothers as well, begging for Murong Sheng's life, and she was joined by Lan Han's wife Lady Yi.
Further, at this time, because of a severe drought, Lan Han went to pray to the Later Yan ancestral temples and Murong Bao's spirit, blaming Murong Bao's murder on Lan Jia'nan.