Osteoarthritis (OA) of the temporomandibular joint (TMJ) is a severe form of temporomandibular disorders (TMDs), presenting gradual breakdown of articular cartilage and subchondral bone by the functional load sustained to exceed the physiologic tolerance of the joint. In such a joint loaded, offensive bioactive materials such as matrix degrading proteins, cytokines, and free radicals increase in concentration to shift the tissue response in the joint to degeneration from regeneration or remodeling. Recently, it has been issued that obesity can play an offensive role in pathogenesis of OA in a metabolic way. Adipokines released by adipose cells are present at higher concentration in the arthritic joint and joints of obese individuals. However, because of conflicting data reported, further scientific study should be performed to elucidate the practical role of adipokines in pathogenesis of TMJ OA. As far as the clinical signs and symptoms of TMJ OA are not much different from those of other forms of TMD and any definitive treatment modality to control directly the bone resorptive activity is not available yet, the treatment of TMJ OA should be directed to reduce the physical load and enhance the physiologic tolerance of the joint by means of conservative treatment such as physical therapy, medication, and occlusal splint therapy for sufficient period and, if needed after that, supplementary surgical procedure such as intra-articular injection, arthrocenthesis, and arthroscopic surgery that have turned out to be effective to control OA signs and symtpoms. Enthusiastic reassurance and motivation for patients to control behaviors for themselves to reduce unnecessary functional load in daily life is very important for the joint to reach to more favorable orthopedic stability of the TMJ more quickly, guaranteeing more successful management TMJ OA.