Emperor Lizong of Song (26 January 1205 – 16 November 1264), personal name Zhao Yun, was the 14th emperor of the Song dynasty in China and the fifth emperor of the Southern Song dynasty. He reigned from 1224 to 1264. Although he was a descendant of the Song dynasty's founder Zhao Kuangyin (Emperor Taizu) and hence a member of the imperial clan, Zhao Yun was not in line to succeed to the throne as his family had no political status. Shi Miyuan (史彌遠), who was the chancellor for many years, collaborated with Empress Dowager Yang and brought Zhao Yun to the throne.
Emperor Lizong's long reign of 40 years did little to improve the predicament of the Song Empire in his time. The emperor was uninterested in governmental affairs, and for the first decade of his rule he delegated matters into the hands of his ministers, notably Shi Miyuan, who was the de facto ruler in his absence. After Shi Miyuan's death in 1233, Emperor Lizong assumed full authority briefly but again quickly abandoned the responsibility of ruling and delegated matters to his chancellor Ding Daquan in order to pursue personal enjoyment. It was said that the emperor frequented brothels and invited prostitutes into the palace, which was vehemently opposed by his ministers.
Notable events during Emperor Lizong's reign included the demise of the Jurchen-led Jin dynasty in 1234, which was obliterated by the joint forces of the Mongol Empire and Song Empire. The Jurchens had fought multiple wars with the Song Empire decades before it was conquered by the Mongols. However, in 1259, the Mongols turned against the Song Empire. The Song government was forced to capitulate and cede all territories north of the Yangtze River to the Mongols. In 1279, the Mongols would eventually conquer the rest of the Song Empire.
Emperor Lizong died childless (his children died prematurely) and was succeeded by his nephew, Zhao Qi (Emperor Duzong).