This study adopts a cultural ecological perspective to examine how cumulative effects of external transcultural and cultural strengths are related to baseline and changes in three markers of Mexican-origin adolescents' self-growth (i.e., resilience, life meaning, and discipline). Using a three-wave longitudinal data set (5 years) of 604 adolescents, cumulative strengths (CS) was calculated, and growth curve analyses showed a similar pattern of findings for both transcultural and cultural cumulative strengths models: Adolescents with higher CS showed higher baseline resilience, life meaning, and discipline. While there were no significant associations between adolescents' CS scores and the increase in resilience, adolescents with higher CS scores showed steeper declines in life meaning and discipline (although these declines were no longer significant for cultural CS when transcultural and cultural CS were simultaneously tested in the same model). The findings emphasize a cultural ecological understanding of Mexican-origin youths' positive development from early to later adolescence. They also provide support for a CS model and have implications for positive psychology theories.