The Goryeo–Khitan War, fought between the Goryeo dynasty of Korea and the Khitan-led Liao dynasty of China, involved several conflicts across the 10th and 11th centuries near today's China-North Korea border. The backdrop of these wars is rooted in the earlier territorial changes following the fall of Goguryeo in 668, with subsequent shifts in power as the Göktürks were ousted by the Tang dynasty, the rise of the Uyghurs, and the emergence of the Khitan people who founded the Liao dynasty in 916. As the Tang dynasty fell, the Khitan grew stronger, and relations between Goryeo and Khitan soured, particularly after the Khitan conquest of Balhae in 926 and Goryeo's subsequent northern expansion policies under King Taejo.
Initial interactions between Goryeo and the Liao dynasty were somewhat cordial, with exchanges of gifts. However, by 993, tensions escalated into open conflict when the Liao invaded Goryeo, claiming a force of 800,000. A military stalemate led to negotiations and an uneasy peace was established, with Goryeo severing ties with the Song dynasty, paying tribute to the Liao, and expanding its territory northward to the Yalu River after expelling Jurchen tribes. Despite this, Goryeo maintained communications with the Song dynasty and fortified its northern territories. Subsequent invasions by the Liao in 1010, led by Emperor Shengzong, resulted in the sacking of the Goryeo capital and continuous hostilities, despite the inability of the Liao to maintain a significant presence in Goryeo lands.
The third major invasion in 1018 marked a turning point when General Kang Kamch'an of Goryeo employed a strategic dam release to ambush and inflict heavy casualties on Liao forces, culminating in the significant Battle of Gwiju where Liao troops were nearly annihilated. The persistent conflict and the devastating losses incurred by the Liao during this invasion eventually led both states to sign a peace treaty in 1022, concluding the Goryeo–Khitan War and stabilizing the region for a period.