Massage therapy is included as part of a comprehensive treatment plan for patients with temporomandibular disorders (TMDs). However, it displayed varying degrees of success. Preexisting psychosocial impairments may be one of the possible factors affecting the treatment response. This preliminary study aimed to investigate the relationships between psychological factors and treatment outcomes of massage therapy in myogenous TMD patients. Twenty-two myogenous TMD patients were enrolled in this single-arm preliminary study. Baseline psychosocial assessment was done using self-report measures associated with chronic pain severity, depression, anxiety, and non-specific physical symptoms. Massage therapy including the intraoral and extraoral massage of the face and neck muscles was performed twice a week for 4 weeks. Pain intensity and quality of life related to oral health were evaluated as treatment outcomes before and immediately after eight sessions of massage therapy. Regression analyses showed a significant effect of depression on changes in the quality of life after massage (β = 0.35, p-value = 0.026). In addition, results showed a significant effect of chronic pain severity on changes in the pain intensity following massage (β = 1.50, p-value = 0.027). Our findings suggested that psychosocial characteristics of myogenous TMD patients should be considered as important factors that may adversely affect pain intensity reduction and quality-of-life improvement after short-term massage therapy.