Riyadh had grown from a small town of less than half a million inhabitants into a large metropolis of more than 6 million during the past fifty years. The speed and scale of its transformation have had few parallels. This article traces the city urban development and its expansion and growth. It is divided into six stages: the first and second stage set up the base for the city development up to the mid 1960’s; the third covers the Doxaidis master plan in late 1960’s; the fourth covers the oil boom of mid 1970’s and SCET’s update of the master plan; the fifth covers ADA efforts to manage the city urban growth in the 1980’s and 1990’s; the sixth covers the MEDSTAR project, its updates and the initiation of Riyadh Public Transport Network (RPTN) in 2012. These initiatives are briefly analyzed and discussed to understand how the city reached its present physical formation. The paper concludes that Doxiadis plan with its supergrid and the superblock of 2 × 2 km provided a rational logical system for the city to expand endlessly. Both SCET and MEDSTAR had followed its approach, method and instruments but at a larger scale. However, two of MEDSTAR proposition, the subcenters and the RPTN project, represent a major departure from the original Doxiadis plan and are expected to change the city’s urban order and structure.