The Zein-o-Din Caravanserai (زين الدين) is located in Zein-o-din, Yazd, Iran. The caravanserai dates to the 16th century and is situated on the ancient Silk Road. It is one of 999 such inns that were built during the reign of Shah Abbas I to provide facilities to travelers. Of these, Zein-o-din is one of two caravanserais built with circular towers. After its refurbishment, it has operated as an inn. A similarly built caravanserai near Esfahan is in ruins.