Data were collected from 310 6th, 7th, and 8th grade students and parents by questionnaires and analyzed by t-test and multiple regression analysis. The higher parents attachment and parents monitoring, the higher prosocial behavior towards patents and siblings, the higher perspective-taking, the higher prosocial behavior towards parents, and the higher socioeconomic status, the higher prosocial behavior towards siblings. More prosocial behavior toward parents was reported by girls than by boys. Prosocial behavior toward siblings did not show a gender difference. In the total group, high parent attachment and perspective-taking predicted prosocial behavior towards parents; high parent attachment and socioeconomic status predicted prosocial behavior towards siblings. In the boy group, high parent attachment and perspective-taking predicted prosocial behavior towards parents; high socioeconomic status predicted prosocial behavior towards siblings. In the girl group, high parent attachment predicted prosocial behavior towards parents and high parent attachment and socioeconomic status predicted prosocial behavior towards siblings. Discussion focused on the relative importance of parents attachment, perspective-taking, and socioeconomic status in predicting early adolescents' prosocial behavior.