["Journal of Research on Adolescence, Volume 36, Issue 2, June 2026. ", "\nAbstract\nThis longitudinal study concerns initial levels, trajectories of growth, and associations of positive youth development (PYD) with parental warmth and behavioral control from early adolescence to young adulthood. Participants included 1338 adolescents (M = 13.25, SD = 1.04, years; 50% girls) from nine countries trichotomized by income level based on World Bank groupings of economies as well as cultural, sociological, and psychological considerations. Composite measures of PYD at ages 13, 15, 16, 18, and 21 were created from adolescent‐report EPOCH dimensions of engagement, perseverance, optimism, connectedness, and happiness. Adolescents reported a high average initial level of PYD (3.50 on a 4‐point scale) at 13 years of age; however, developmental trajectories of each income‐level group differed with little within‐group variation across age. Multigroup latent growth curve models examined associations of family‐level and parent‐specific dimensions of warmth and control with intercepts and trajectories of PYD. Parental warmth was consistently associated with higher PYD intercepts in all three country income levels, whereas control showed varied effects. PYD followed similar trajectory slopes across the three country income levels; parental warmth was consistently associated with growth, whereas parental control showed nuanced associations with parent and country. Warmth appears to act as a common protective correlate of adolescent PYD, whereas control appears to constitute a protective correlate in some cultural contexts but a risk correlate in other cultural contexts.\n"]