Zoning, a powerful institution for shaping urban development, is most closely tied to the practice of urban planning. Planners thus need to be deeply conversant with the potential of this complex institution to reflect and transmit values about the city. With evidence from cases past and present, this chapter demonstrates how the practice of zoning occurs through institutions far beyond formal regulations: the norms and values, discourses, transactions, networks, laws, and working rules that shape the processes of land use regulation and decision making. Situating zoning firmly as a political and value-laden institution opens new territories of meaningful intervention.