Parental attachment has been argued to play a fundamental role in the development of adolescent Internet morality. However, little is known about the mediating and moderating mechanisms of parental attachment. The present study tested a moderated mediation model that included parental attachment (predictor variable), empathy (moderator), online social support (mediator), and Internet morality (outcome variable) in a sample of 2178 participants aged 12-25 years (M[subscript age] = 19.61, SD = 2.39) recruited in a school setting. After controlling for gender, age, and family socioeconomic status, multivariate multiple regression indicated that secure parental attachment was positively associated with adolescent online social support, which in turn was positively associated with Internet morality. Moreover, adolescents' empathy moderated the relationship between parental attachment and online social support. This association was stronger for adolescents with higher empathy than with lower empathy. These findings improve our understanding of the underlying mechanisms whereby these factors interactively influence adolescent Internet morality; furthermore, they hold important implications for effective intervention.