Game theory has been one of the most prominent theories in the social sciences, influencing diverse academic disciplines such as anthropology, biology, economics, and political science. In recent years, economists have employed game theory to investigate behaviors relating to fairness, reciprocity, and trust. Surprisingly, this research has not found much resonance in psychological research on social development, even though the two disciplines share a common interest in explaining similar social behaviors and phenomena. We argue that combining economic game theory with developmental psychology can prove to be valuable for both disciplines: developmental psychology can contribute its knowledge about the ontogenesis of social abilities and competencies to economic research, thus providing economists with new theories and understanding. Game theory, on the other hand, can offer developmental psychologists new methodologies and tools for investigating social development.