Bronfenbrenner's bioecological theory of human development is one of the most widely known theoretical frameworks in human development. In spite of its popularity, the notion of culture within the macrosystem, as a separate entity of everyday practices and therefore microsystems, is problematic. Using the theoretical and empirical work of Rogoff and Weisner, and influenced as they are by Vygotsky's sociocultural perspective, we reconceptualize Bronfenbrenner's model by placing culture as an intricate part of proximal development processes. In our model, culture has the role of defining and organizing microsystems and therefore becomes part of the central processes of human development. Culture is an ever changing system composed of the daily practices of social communities (families, schools, neighborhoods, etc.) and the interpretation of those practices through language and communication. It also comprises tools and signs that are part of the historical legacy of those communities, and thus diversity is an integral part of the child's microsystems, leading to culturally defined acceptable developmental processes and outcomes.