This chapter comprehensively reviews the effects of crystallographic orientation and grain boundary character distribution (GBCD) on corrosion resistance of materials. The first section of the chapter highlights the impact of microtexture, formed through deformation and surface modification processes, on various forms of corrosion at ambient and elevated temperatures. The role of crystallographic planar density in controlling electrochemical dissolution rates is explored in details. The {111}, {110}, and {0001} crystallographic planes with highest packing densities are observed to offer the maximum resistance to electrochemical degradation in FCC, BCC, and HCP materials, respectively, due to their lowest surface energies. The chapter also delves into the influence of orientation relationship existing between the neighboring grains in determining the corrosion response. Adjacent grains with misaligned orientations may increase corrosion susceptibility through mechanisms such as micro-galvanic effects. Additionally, the effect of preferred crystal growth directions during processes like surface modifications and coatings is examined, showing how directional growth can either enhance or reduce corrosion resistance. In the latter part of the chapter, the focus shifts to mesotexture, particularly highlighting the role of GBCD in corrosion behavior. Microstructures with a higher fraction of Σ3ⁿ (n = 1, 2, 3) boundaries are found to be more resistant to corrosion due to their lower interfacial energy, compared to random high-angle grain boundaries. The importance of optimizing grain boundary characteristics to improve material performance in corrosive environments is also elaborated. Overall, the review establishes that both microtexture and GBCD are critical factors in tailoring corrosion resistance, suggesting pathways for future research and practical applications in materials engineering.