Emperor Gaozong of Song (12 June 1107 – 9 November 1187), personal name Zhao Gou, courtesy name Deji, was the tenth emperor of the Song dynasty in China and the first emperor of the Southern Song dynasty.

He was the ninth son of Emperor Huizong and a younger half-brother of Emperor Qinzong. In 1127, during the wars between the Song dynasty and Jurchen-led Jin dynasty, the Song capital Bianjing (present-day Kaifeng) fell to Jin forces in an event historically known as the Jingkang Incident. Emperors Huizong and Qinzong were taken prisoner by the Jurchens, while Zhao Gou managed to escape to southern China. He reestablished the Song dynasty (as the Southern Song dynasty) in Lin'an (present-day Hangzhou) and was proclaimed emperor. He reigned from 1127 until 1162, when he abdicated the throne in favour of his adopted son Zhao Shen (Emperor Xiaozong), and became a Taishang Huang ("Retired Emperor") until his death in 1187. He was a capable ruler who brought stability to the Song but was criticized by his reputation of sentencing his court members with trumped-up charges including Yue Fei, whom he executed.

He was the last descendant of Emperor Taizong to become emperor; subsequent Song emperors were descendants of Emperor Taizu.