BACKGROUND: The longitudinal associations between oral health (OH) and physical and mental health-related quality of life (HRQoL) are unclear. PURPOSE: This study examined the relationship of self-reported OH with the trajectories of physical and mental HRQoL in Hong Kong at 3, 9, and 15 months after the measurement period using a latent growth curve model. METHODS: This study included 5,710 participants recruited in the FAMILY project cohort study during March-October 2009. Self-report OH was measured using a five-point single-item scale, and HRQoL was measured using the physical component scale (PCS) and mental component scale (MCS) of Short Form 12. Latent growth curve model was used to compute the relationship of self-reported OH with the trajectories on HRQoL over time, adjusted for age and sex. RESULTS: The latent growth curve model gave good fit to both the PCS (normed fit index (NFI) = 0.98, comparative fit index (CFI) = 0.99, and standardized root mean square residual (SRMR) = 0.03) and MCS (NFI = 0.97, CFI = 0.98, and SRMR = 0.03). Better self-reported OH was associated with higher PCS and MCS at the baseline. The longitudinal association with PCS remained constant over time (coefficient = -0.02, p = 0.07) but that with MCS diminished over time with baseline oral health status (coefficient = -0.04, p = 0.002). CONCLUSION: Better self-reported OH status was associated with higher level of physical and mental HRQoL, and with negative change in mental HRQoL.