<p>Grain boundaries (GBs) are essential in defining the mechanical characteristics and behavior of any polycrystalline material. Their presence has been known to impact the various properties of the materials, including mechanical, thermal, electrical, and optical properties. Interestingly, specific GBs are known to form special faceted structures wherein they adopt a series of distinct planar segments or facets. The presence of faceted GBs has been linked with the anisotropic nature of GB free energies with respect to their inclination, introducing distinct characteristics that significantly influence the overall performance and functionality of materials. Moreover, the formation of faceted GBs increases the total boundary area due to the creation of additional facets. However, as these facets are more energetically favorable, the formation of these faceted GBs leads to a reduction in the overall GB energy. Further, their migration behavior contrasts significantly with that of non-faceted GBs. Understanding the nature of faceted GBs is crucial since they have been closely associated with phenomena such as abnormal grain growth, GB migration, wetting, and diffusion, all of which can result in significant variations in the material’s mechanical, electrical, and thermal properties. In this extensive review article, we have discussed in depth the alteration in the material’s performance incorporated with faceted GBs. Both the experimental and simulation-based investigations have been critically examined and reported to present an informed perspective on recent advancements in this field. Key findings revealed how the faceted GBs contribute to the unique stress responses and alter the energy of the structure, underscoring their role in altering material performance. Finally, we have highlighted prospective research avenues that could help in deepening our understanding of faceted GBs and their impact on material properties.</p> Graphical Abstract <p></p>