The Qays–Yaman rivalry refers to the historical rivalries and feuds between the northern Arabian Qays tribes and the southern Arabian Yaman tribes. The conflict emerged among the tribes within the Umayyad Caliphate's army and administration in the 7th and 8th centuries. Membership in either faction was rooted in real or perceived genealogical origins of the tribes, which divided them into south Arabian descendants of Qahtan (Yaman) or north Arabian descendants of Adnan (Qays).