["Journal of Research on Adolescence, Volume 36, Issue 3, September 2026. ", "\nAbstract\nAdolescent self‐rated health (SRH) is a robust predictor of long‐term health, but less is known about how local psychosocial resources influence its development in adolescence. We explored whether social capital, captured as both household‐level (i.e., parents' social embeddedness in their neighborhood) and community‐level (i.e., average stocks of social capital in the area), influences trajectories of SRH in early and middle adolescence in the United Kingdom. Using data from the UK Household Longitudinal Study, we tracked a sample of 2413 adolescents, aged 10–15 years at baseline, over a 5‐year follow‐up period. Latent Variable Autoregressive Latent Trajectory (LV‐ALT) models, within a structural equation modeling framework, captured both the stability and changeability of SRH over time, assessing the influence of baseline levels of social capital, adjusting for key sociodemographic and psychosocial characteristics. SRH showed high stability at the population level over 5 years. Higher household “cognitive” social capital scores at baseline were associated with better initial SRH (β = .09, p < .01) and higher household “network” social capital predicted positive changes in SRH over time (β = .02, p < .05). Community‐level social capital was not associated with either baseline or changing SRH. Girls reported lower baseline SRH (β = −.08, p < .001) and experienced more pronounced declines over time than boys (β = −.05, p < .001). Overall, household‐level social capital, specifically parental embeddedness within local neighborhoods, plays distinctive roles in supporting early and middle adolescent SRH, highlighting the importance of local family and neighborhood connections for healthier trajectories. Investing in these forms of social capital may promote healthier adolescent development.\n"]