The temporomandibular joint (TMJ) is a ginglymo-diarthrodial synovial joint. Its principal components are the fossa-eminence of temporal bone, the mandibular condyle, and a fibrocartilagenous articular disc known as the TMJ disc. TMJ movements are more complex than most synovial joints. The TMJ disc plays a key role in these movements by distributing load, absorbing shock, and lubricating surfaces. The extracellular matrix (ECM) of the TMJ disc is primarily composed of collagen type I, which forms a ring-like structure around the periphery of the disc and in the anteroposterior direction in the intermediate zone. Glycosaminoglycans, proteoglycans, and elastin fibers also form the ECM. The cell types of the disc include a nonhomogeneous distribution of fibroblasts and chondrocyte-like cells; these cells serve to maintain the ECM of the TMJ disc. The mechanical properties of the disc are mostly unknown because of large variations between animal models and test methodologies; however, it is believed that the TMJ disc is primarily a tensile tissue. Several disorders, including internal derangements, degenerative diseases, and reparative/osteogenic diseases, are associated with an injured or displaced disc. These disorders affect about 2–4% of the population and greatly reduce the quality of a patient's life, afflicting everyday activities such as eating, talking, and laughing. Treatments for severe temporomandibular dysfunction are available, but alleviation of joint problems without future repercussions is difficult. Biomedical engineering continues to work toward better solutions for temporomandibular dysfunction by developing innovative treatments and fully characterizing the components and diseases of the TMJ.