Yazd is the capital of Yazd Province, Iran, and a centre of Zoroastrian culture. The Zein-o-Din Caravanserai 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, Zeinodin 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.

The caravanserai is a two-storied structures, square in plan, with a courtyard and a water pool. Only two caravanserais have been built with circular towers.