In recent years, studies have extensively explored both personal and environmental predictors of cyberbullying. Among these predictors, parental monitoring and school climate were often expected to be associated with cyberbullying behaviors. However, little is known about the mediating mechanisms through which these relations may develop. The present study aimed to expand the current research by testing a theoretical model including the mediating role of moral disengagement in the relations between parental monitoring (including less collaborative vs. more collaborative strategies), school climate, and cyberbullying behaviors. Five hundred and seventy-one Italian adolescents (54.5% male) aged 14 to 20 years were recruited from high schools. Measures included demographics and parental monitoring, school climate, moral disengagement and cyberbullying scales. To test the hypothesized model, we estimated full and partial mediation models by structural equation modeling. Results showed negative indirect links of parental monitoring (but only the more collaborative strategies) and school climate with cyberbullying via moral disengagement. Less collaborative strategies of parental monitoring were neither directly nor indirectly related to cyberbullying. The findings revealed moral disengagement as an important process in explaining how ecological factors, such as parenting behaviors and school environments, are associate with cyberbullying. Limitations, strengths, and implications for practice are presented.