The present study investigated if values and social axioms predict prosocial behavior, as well as the incremental validity of social axioms, beyond values in the prediction of prosocial behavior. Considering that there is no evidence in the scientific literature for studies that explore the relationship of these three variables, the aim of the study was to fill in this gap. Initially 177 participants took part in the study; in the final analysis, data from 155 participants was included. Participants could access the questionnaires on social networks where they had to complete four trials of the Ultimatum and Dictator Game, the Prosocialness Scale (Caprara et. al, 2005), the Romanian version of the second edition of Social Axioms Survey (SAS-II; Leung et al., 2012) and the Value Survey of Schwartz (1992). Results showed that social axioms have incremental validity over and beyond values in the prediction of prosocial behavior – measured objective and subjective. These results bring evidence for values and social axioms explaining a significant part of the variance of the prosocial behavior. In addition, social axioms have a significant predictive power beyond values. This study has a theoretical and a practical contribution, as well. It contributes to the development of the culture, as a concept by adding the notion of social axioms and has a practical contribution for planning interventions that focus on changing the way people cooperate or modifying the helping tendencies of people.