Adolescence entails a series of changes in young people who need to adopt socially positive behaviours and have a beneficial family and school environment. The main objective of this research is to analyse the relationships established between the variables of prosocial behaviour and school climate, as well as to check whether family functionality plays a moderating role in this relationship. The participants were a total of 743 adolescent students between 14 and 19 years of age from different schools in the province of Almería (Spain). The instruments used to evaluate the young people were the APGAR family functioning scale, the Prosocial Behavior Questionnaire (CCP) and the School Social Climate Questionnaire (CECSCE). The data analysed showed a positive correlation between all the variables analysed: family functioning, prosocial behaviour and school climate. Gender differences were found, with adolescent girls showing higher levels of empathy and respect, while boys scored higher in social relations and school climate. The results indicate that family functioning plays a moderating role in some dimensions of prosocial behaviours and school climate. The importance of attending to these types of variables in adolescent students to foster optimal youth development and promote their personal well-being is discussed.