The anterior longitudinal ligament (ALL) is a strong, collagen-rich structure that extends from the occiput to the sacrum along the anterior surface of the vertebral column. It plays a critical role in spinal stability by limiting hyperextension and supporting anterior vertebral alignment. The ALL is composed of layered collagen fibers with limited elastic content, and its morphology varies by spinal region. Despite its importance, histological and morphometric data on the ALL remain limited and inconsistently described. This review consolidates anatomical, biomechanical, and clinical findings on the ALL, including its embryological development, layered fiber structure, and relationship to adjacent structures such as the anulus fibrosus and diaphragm crura. Biomechanically, the ALL exhibits high stiffness and tensile strength, particularly in younger individuals. Clinically, it is involved in hyperextension injuries and in pathological ossification seen in diffuse idiopathic skeletal hyperostosis, particularly in the cervical spine, where it can contribute to dysphagia or radiculomyelopathy. The ALL is also a key structure encountered during anterior cervical and lumbar spinal surgeries. A comprehensive understanding of its structure and function is essential for accurate diagnosis, surgical planning, and management of spinal disorders.