We evaluated the correlation between oral health-related quality of life (OHRQoL) and the Helkimo clinical dysfunction index (HDI) in patients with temporomandibular joint osteoarthritis (TMJ OA). Clinical data and scores for the Chinese version of the 14-item Oral Health Impact Profile (OHIP-C14) were recorded and analyzed for 541 patients with TMJ OA. Each patient was assigned an HDI score of 1 to 25, which was used to classify severity into three categories. OHRQoL was assessed by using OHIP-C14 score, which ranged from 0 to 56. Both HDI score and severity were significantly correlated with total OHIP-C14 score (P < 0.001 for both comparisons). The scores for all HDI domains except function impairment (P = 0.205) were significantly correlated with OHIP-C14 score. The scores for all seven OHIP-C14 domains were significantly correlated with HDI score and severity. Several correlations between OHIP-C14 domains and HDI domain scores were significant. HDI score and severity were correlated with OHIP-C14 score in TMJ OA patients. As compared with function-related domains, pain-related HDI domains were more strongly inversely related to OHRQoL.(J Oral Sci 58, 483-490, 2016).