On November 18, 1967, Tehran introduced its first high-rise regulation code to manage urban expansion and support vertical growth in the city. The 1960s saw Tehran transforming from a low-rise city to a major metropolitan center, driven by industrial growth and rural-to-urban migration. The code defined maximum building heights, mandatory setbacks, elevator standards, seismic reinforcement requirements, and minimum parking ratios for multi-storey structures. This allowed vertical expansion while reducing central district congestion and mitigating land scarcity issues. Architects and developers gained clear planning guidelines, resulting in better construction quality and a controlled skyline. Over the following decades, the policy guided the creation of high-density corridors and mid-rise housing blocks, forming the basis of Tehran’s modern zoning system. It shaped urban growth patterns, encouraged responsible architectural design, and became a reference for future urban reforms.