Aims: To explore the relationships between sleep quality, perceived pain, and psychologic distress among patients with temporomandibular disorders (TMD). Methods: A total of 137 consecutive patients who sought care at the University of Kentucky Orofacial Pain Center for the management of TMD participated in this study and completed a battery of standardized, self-report questionnaires at their first clinic visit. The Pittsburgh Sleep Quality Index (PSQI) and the Multidimensional Pain Inventory (MPI) were used to measure patients' sleep quality and multiple dimensions of pain and suffering, respectively. The Revised Symptom Checklist-90 (SCL-90R) was used to evaluate psychologic symptoms. A median cutoff (PSQI total score: 10) divided the patients into 2 groups, ie, 67 poor sleepers and 70 good sleepers. Results: There were no statistically significant differences in gender and age distributions between the 2 groups. Poor sleepers reported significantly higher scores than good sleepers on each of the 14 scales of the SCL-90R (P .003) and on 7 of the 13 scales of the MPI (P .05). Stepwise multiple regression analyses demonstrated that poorer sleep quality was predicted by higher pain severity (P .001), greater psychologic distress (P .05), and less perceived life control (P .05). Conclusion: This study supports the frequent comorbidity of reported sleep disturbance, perceived pain severity, and psychologic distress in patients with TMD. Keywords: temporomandibular disorders, sleep quality, psychological tests