Objective <p>Depressive symptoms are prevalent, heterogeneous conditions involving physical and psychological manifestations, and are associated with impairment of health-related quality of life (HRQoL). We aimed to estimate the association between depressive symptoms, lung function trajectories, and HRQoL in aging individuals, and explore whether lung function trajectory explains part of the association between depressive symptoms and HRQoL in ageing population.</p> Methods <p>This study used data from waves 2, 4, 6, and 7 of the Survey of Health, Ageing and Retirement in Europe (SHARE), comprising 7848 observations from participants aged 50 years and older across multiple European countries. Group-based trajectory modelling identified distinct longitudinal trajectories of lung function by sex. Multinomial logistic regression was used to examine the associations of depressive symptoms and lung function trajectories with HRQoL. To assess whether the association between depressive symptoms and HRQoL could be explained by an indirect pathway involving lung function trajectory, a parallel-process latent growth curve model was performed.</p> Results <p>A strong dose-response relationship was observed between the cumulative exposure level of depressive symptoms, lung function trajectories, and HRQoL. The longitudinal analysis revealed that the association between depressive symptoms and HRQoL was partially accounted for by an indirect association involving lung function trajectory. A statistically significant indirect effect of depressive symptoms on HRQoL through the intercept of lung function was observed in both males and females.</p> Conclusions <p>The findings underscore that depressive symptoms, lung function decline, and HRQoL are interrelated in the aging population. This suggests that strategies addressing depressive symptoms could be relevant for comprehensive care aimed at preserving lung health and HRQoL.</p>