Evidence shows that tenth- and eleventh-century Kitan (Liao) emperors used pseudo-kinship to cement diplomatic relations with foreign powers as well as for internal affairs. Similarities between this practice and twelfth- and thirteenth-century Mongol anda (sworn friendship) were previously highlighted by Wang Guowei but have yet to be the focus of further study. Kitan emperors used pseudo-kinship as a preferred political tool to establish alliances and reinforce their position in both external and domestic policies. A comparison of Kitan and Mongol traditions also shows a high degree of similarity. However, although they share concepts of sworn friendship and common oath rituals, the establishment of pseudo-kinship occurred in different contexts and often for different purposes. This article attempts to show that Kitan rulers successfully continued the pseudo-kinship diplomacy that existed since the Tang between the hegemons of the steppe and the Central Plain. They achieved this by making regular use of pseudo-kinship diplomacy, in addition to seeking ways to make the practice more acceptable to the Chinese court. These adaptations included a progressive estrangement of diplomatic pseudo-kinship from its original form, casting away oath rituals and adopting a new system of kinship terms.