Sar Yazd Castle (Qal’eh Sar Yazd in Persian) is a historical castle built during Sassanid Dynasty (the 3th_ 7th century) in Sar Yazd village, Mehriz county, Yazd Province, Iran.
The castle has been one of the oldest and largest bank safe-deposit boxes in Iran and the world where cereals, money, gold and jewelry were kept during invasions. The castle has nested concentric walls with impregnable high towers that is surrounded by a moat. The moat has a width of 6 meters and a depth of 3 to 4 meters.  The castle has two doors, that one is a main door and another is a guardian door. The castle has three floors that are made with mud brick.
Sar Yazd Castle was registered in national index by the Iranian Cultural Heritage Organization with number 1084 in 1975.