Objectives This study aimed to identify baseline factors that predict Health-Related Quality of Life (HRQoL) in patients with TMD 8 years later. Materials and Methods 401 participants (333 women, mean age 45.8 years) from a multicenter cohort were examined using the Diagnostic Criteria for TMD (DC/TMD) and questionnaires. The main outcome was the 12-item Short Form Health Survey (SF-12), a HRQoL measure that provides physical (PCS) and mental (MCS) summaries. Baseline predictors included age, gender, self-reported health, Jaw Functional Limitation Scale (JFLS), pain intensity, pain frequency, and pain duration. Regression analysis with stepwise modeling identified predictive factors. Results 54.3% had painful TMD, 15.7% had nonpainful TMD, and 27.7% were healthy controls. For the painful TMD group, the regression model was significant (R-2 = .25, F = 4.3, P < .01), with age and favorable general health predicting PCS scores. In the nonpainful TMD group, the model was significant (R-2 = .58, F = 3.8, P < .01), with JFLS and favorable general health (predicting PCS scores. The MCS model was significant in healthy controls (R-2 = .22, F = 1.8, P = .05), with JFLS as only predictor. Conclusion Predictors of mental HRQoL: JFLS in healthy controls, but no predictors were found in TMD groups. Predictors of physical HRQoL: General health in both TMD groups, JFLS in the nonpainful TMD group, and age in the painful TMD group.