The urban environment is a result of the interaction of various variables, which include characteristics of the site, characteristics of actors involved in urban development, planning policy and the economic context. Within this perspective, this paper aims at examining the role of the actors on urban development by first, defining these actors, and second analysis their role in urban development. It is assumed that there is a wide range of actors which necessitate grouping them according to their interests and roles. Defining actors' role will enrich our understanding about our cities and urban areas, and paves the way for policy makers to estimate effects of planning policies on various actors and on urban development, especially as we are entering a new century. Theme of the paper focus on the Saudi experience.