This study explores how peer influence and parental emotional support affect behavioral adjustment in youth, with self-esteem examined as a moderating factor. Using a quantitative design, survey data from adolescents were analyzed through SPSS, employing reliability testing, exploratory factor analysis, multiple regression, and moderation analysis. The findings show that peer influence (β = 0.484) has the strongest impact on behavioral adjustment, while parental emotional support (β = 0.32) also plays a meaningful role by fostering stability and emotional security. Self-esteem emerged as a significant moderator (β = 0.29), softening the extent to which peer pressure translates into adjustment outcomes. These results add nuance to existing theories of adolescent development by illustrating how external relationships and internal strengths interact to shape behavior. Practically, the study highlights the importance of cultivating self-esteem, reinforcing parental support, and fostering positive peer environments to promote healthier adjustment. Together, these insights offer guidance for educators, parents, and policymakers working to support adolescent well-being.