Collagen is a key component of bone strength, influencing its mechanical properties through its interactions with minerals and its structural organization. Bone strength depends on both the quantity and quality of bone tissue, with quality determined by factors such as bone geometry, microarchitecture, turnover, mineral content, and collagen. The interplay between mineral and collagen is complex, and their specific roles in bone strength are challenging to analyze. Type I collagen, the most abundant collagen in bone, forms triple-helix structures and is arranged in fibrils that provide ductility and energy absorption. The mechanical properties of bone are influenced by the organization of collagen fibers, which can be affected by enzymatic and nonenzymatic processes. Enzymatic processes, such as the activation of lysyl oxidase, lead to the formation of crosslinks that stabilize collagen fibrils. Nonenzymatic processes, including the formation of advanced glycation end products and racemization/isomerization in collagen telopeptides, can alter collagen properties and impair bone strength. These modifications are age-related and may contribute to bone fragility. Disorders such as osteogenesis imperfecta and osteoporosis are associated with collagen abnormalities and bone fragility. Bone matrix is a two-phase system, with mineral providing stiffness and collagen providing ductility and energy absorption. The synthesis and structure of type I collagen involve complex posttranslational modifications, including hydroxylation of proline and lysine, and the role of chaperones in folding. The C-propeptide is essential for maintaining procollagen solubility during trafficking, while the N-propeptide influences fibril shape and diameter. The triple-helical structure is stabilized by posttranslational modifications that allow crosslinks between collagen fibrils, mediated by lysyl oxidase. These crosslinks are crucial for bone strength and are affected by age-related changes in collagen. Understanding the role of collagen in bone strength is essential for the diagnosis and treatment of bone-related disorders.Collagen is a key component of bone strength, influencing its mechanical properties through its interactions with minerals and its structural organization. Bone strength depends on both the quantity and quality of bone tissue, with quality determined by factors such as bone geometry, microarchitecture, turnover, mineral content, and collagen. The interplay between mineral and collagen is complex, and their specific roles in bone strength are challenging to analyze. Type I collagen, the most abundant collagen in bone, forms triple-helix structures and is arranged in fibrils that provide ductility and energy absorption. The mechanical properties of bone are influenced by the organization of collagen fibers, which can be affected by enzymatic and nonenzymatic processes. Enzymatic processes, such as the activation of lysyl oxidase, lead to the formation of crosslinks that stabilize collagen fibrils. Nonenzymatic processes, including the formation of advanced glycation end products and racemization/isomerization in collagen telopeptides, can alter collagen properties and impair bone strength. These modifications are age-related and may contribute to bone fragility. Disorders such as osteogenesis imperfecta and osteoporosis are associated with collagen abnormalities and bone fragility. Bone matrix is a two-phase system, with mineral providing stiffness and collagen providing ductility and energy absorption. The synthesis and structure of type I collagen involve complex posttranslational modifications, including hydroxylation of proline and lysine, and the role of chaperones in folding. The C-propeptide is essential for maintaining procollagen solubility during trafficking, while the N-propeptide influences fibril shape and diameter. The triple-helical structure is stabilized by posttranslational modifications that allow crosslinks between collagen fibrils, mediated by lysyl oxidase. These crosslinks are crucial for bone strength and are affected by age-related changes in collagen. Understanding the role of collagen in bone strength is essential for the diagnosis and treatment of bone-related disorders.