Jia Sidao (賈似道, 1213–1275) was a chancellor during the late Song Dynasty of China. He dominated the Song court from 1260 to 1273, after rising to the rank of chancellor due to his sister being a concubine of the Emperor Lizong. Known for his corruption and incompetence, he was most famous for his intervention in the Battle of Xiangyang, in which he hid the true situation from the Song court, and was responsible for its demise. In addition, Jia Sidao pioneered a policy of land nationalization, which was highly unpopular among the Confucians, who favored low taxes and a small role for the state. Later, at the Battle of Yihu, Jia Sidao's incompetence led to a defeat in which the remants of the Song army were routed, leading to the Mongols advancing on the capital, Hangzhou. He was then executed as a result of this defeat.