Korea's Munhwa Ryu clan (문화류씨 [文化柳氏]) is one of the great aristocratic houses of Koryo and Choson society. "Munhwa," which means 'culture,' refers to the clan seat, a township in modern-day Hwanghae province, North Korea. The surname "Ryu" (also Yu [유], commonly romanized "Yoo") comes from the character meaning willow tree, hence the lineage is also called "willow Ryu" (버들류씨).

In the early tenth century AD the clan's progenitor Ryu Ch'a-dal (류차달 [柳車達]) was instrumental in defeating subversive forces and reuniting the kingdom under a new regime, the Koryo dynasty (918-1392). For his loyalty and service King T'aejo (왕건) rewarded Ryu with estates and the title 'Duke of Great Aid' (대승공 [大丞公]).

One of Lord Ryu's two sons adopted the family name Ch'a (차 [車]), and until recently Korean law barred "intermarriage" between Ryus and Ch'as as this was considered incestuous. Marriage between any of S Korea's 270,000 present-day Munhwa Ryus is still culturally taboo.