Modern thin film industries require precise tailoring of thin films properties to have excellent performance at specific applications intended. Atomic scale understanding of the microstructure of polycrystalline thin films is necessary for the control and manipulation of the film properties for a wide range of industrial applications. Thin film growth of thin films influence grain shapes, distribution of grains and the crystallographic orientation of the grains thereby affecting their reliability and performance. This article reviews the present understanding of the mechanism(s) determining the microstructural evolution of polycrystalline films and the related structure zone models. General trends in microstructural evolution, grain morphology and texture formation mechanisms are discussed in terms of their fundamental kinetic processes. The temperature dependency of the film microstructure is described using Thornton structure zone models.