Bone is a remarkable natural material known for its ability to adapt its structure in response to physiological demands. It is also considered a composite material, composed of a tough organic phase, a brittle mineral phase, and water molecules. These components organize at multiple length scales, creating a structure that is both extremely tough and lightweight. Additionally, bone exhibits a remarkable property called mechanotransduction, where it responds to external mechanical loads by dynamically adjusting its morphology through targeted bone deposition or resorption. However, due to disease or aging, a decline in bone quality substantially impairs the skeleton's load-bearing capacity, leading to fractures. Bone fractures are very common in the elderly population suffering from osteoporosis or other metabolic conditions such as diabetes. To prevent fractures associated with poor bone quality, it is crucial to understand the deformation and failure mechanisms of bone at every hierarchical level. Therefore, this review mainly focuses on the molecular mechanisms underlying bone tissue deformation and failure. In-depth understanding of these mechanisms holds promise for the design of targeted treatment regimens and therapeutic interventions tailored to address specific bone pathologies.