Emperor Duzong of Song (2 May 1240 – 12 August 1274), personal name Zhao Qi, was the 15th emperor of the Song dynasty in China and the sixth emperor of the Southern Song dynasty.
He was a nephew of his predecessor, Emperor Lizong, and reigned from 1264 until his death in 1274.
His birth name was Zhao Mengqi but his name was changed to Zhao Zi in 1251 and finally to Zhao Qi in 1253 after he was designated as Emperor Lizong's heir apparent.
Duzong's reign was filled with rebellions and warfare; the court was dominated by his chancellor Jia Sidao and Duzong himself gave in into drinking and women, thus abandoning his duties.
He died in 1274 leaving behind three young boys, one of whom took the throne as Emperor Gong.
He is the last Emperor of the Song to issue coins; subsequent Emperors were too busy fighting the Mongols to establish mints to cast any coins and did not have enough resources.