This Special Issue aims to highlight the latest advancements in the critical areas of characterizations, mechanical properties, and constitutive modeling of advanced materials, integrating both experimental and theoretical perspectives. This collection of works spans a diverse range of topics, from the characterization of cutting-edge materials like nanomaterials and biomaterials to the detailed investigation of their mechanical properties under various conditions. Additionally, it features the development of sophisticated constitutive models that enhance our understanding and prediction of material behavior. By bringing together pioneering research and insights, this Special Issue aspires to contribute significantly to the advancement of materials science and engineering.