In this chapter, all metamorphic rocks of Iran have been studied and evaluated from the perspective of metamorphic facies, protoliths and their relationship with magmatic and orogenic phases. The distribution of metamorphic rocks is described along with the geological map and the grade of metamorphism. The causes of metamorphism and geodynamics of all metamorphic rocks are classified according to their structural zones, in stratigraphic order. Metamorphic rocks are also classified into orogenic phases according to their structural zone: Pan-African orogenic phase in Late Precambrian Caledonian orogenic phase Metamorphic rocks of Hercynian phase Metamorphic rocks of Cimmerian phase Laramide metamorphic rocks Young Alpine metamorphic rocks. In each phase, the distribution of metamorphic rocks, petrography, grade of metamorphism and geodynamics are described in detail. This chapter also evaluates contact-metamorphism in relation to intrusive masses.