An overview is given of cross-cultural psychology and cultural psychology, focusing on theory and methodology. In Section 1 historical developments in research are traced; it is found that initially extensive psychological differences tend to shrink when more carefully designed studies are conducted. Section 2 addresses the conceptualization of “culture” and of “a culture”. For psychological research the notion “culture” is considered too vague; more focal explanatory concepts are required. Section 3 describes methodological issues, taking the notion of the empirical cycle as a lead for both qualitative and quantitative research. Pitfalls in research design and data analysis of behavior-comparative studies, and the need for replication are discussed. Section 4 suggests to move beyond research on causal relationships and to incorporate additional questions, addressing the function and the development of behavior patterns in ontogenetic, phylogenetic and historical time. Section 5 emphasizes the need for applied research serving the global village.