Most cities in developing countries experience unprecedented changes in their physical and social structures during the process of modernization. This article investigates daily life in a modern neighborhood of Tehran, Narmak, designed in 1951 based on Western ideas, through the application of qualitative research methods to examine the transformation of this neighborhood from a Gemeinschaft community to a more urban community. This article uses the public spaces of the neighborhood as a tool to monitor daily life and the changes that have emerged in the neighborhood. It considers the social interactions in the public spaces of the neighborhood as a synthesis between the new norms stemming from the modern culture and the traditional cultural and religious norms reflected in gender, family, and neighborhood relations. The findings reveal that despite Narmak’s modern design and planning, a synthesis between traditional and modern culture can be observed in this neighborhood. Five decades after its design, the original low-density residential neighborhood has been transformed into a mixed-use, medium-density neighborhood with new migrants consisting of half of its population. Observations suggest differences both with the old mahallehs (neighborhoods), such as the blur of the previously more clear-cut public-private boundaries and the use of public spaces by youths and women, and with qualities inherited from traditional mahallehs, such as a sense of community, the exclusion of strangers, cul-de-sacs, and so forth.