This thesis examines the interregional style of Goryeo Water-moon Avalokiteśvara paintings, of which there are 51 around the world. The majority are anonymous, and are found in Japanese collections where they had once been mistakenly attributed to professional Chinese painters. The rediscovery of Goryeo Buddhist paintings in the twentieth century was enabled by an awareness of a “style”, which varied from the neighbouring countries of China and Japan, by groups of Japanese scholars. This ignorance or the uncertainty of the true Korean identity of the corpus of paintings, which had existed for hundreds of years, was in turn shaped by their interregional style and route of transmission. This is explored across the four chapters of this thesis. Chapter one surveys the core information related to connoisseurship, including the inscriptions, titles, Yuan-Goryeo relations and the history of transmission. Chapter two examines the studio production in which artisans created paintings using an assembly line system. The iconography, motifs, settings, and figures depicted in the Goryeo Avalokiteśvara paintings are studied as “movable segments”. The third chapter explores the mobility of the white-robe tradition and the exchanges of artifacts brought about by the travels of two Goryeo royals and the Goryeo embassies sent to China. The final chapter investigates the reasons behind the resemblances between Goryeo Water-moon Avalokiteśvara paintings and the Avalokiteśvara paintings excavated from the Khara Khoto site.