This paper examines the transition of the perception of the suburban from an inherently non-sustainable territory, to a territory holding environmental, social and architectural potential. This is done through a comparative analysis of the suburban of three European countries: Belgium, France and Denmark. The approach identifies urban, architectural, social and environmental constants and variables of each country in order to better illustrate the reasons and nature of this shift of perception. First, the paper provides a comparative insight on legal contexts and urban policies that have favored or limited suburban development. This state of the art highlights how the increasing focus on sustainable development has introduced the concept of suburban transformation as being an integral part of the “urban sutainability” discourse. Finally, a number of case studies of retrofitting initiatives from the three countries are examined. ; This paper examines the transition of the perception of the suburban from an inherently non-sustainable territory, to a territory holding environmental, social and architectural potential. This is done through a comparative analysis of the suburban of three European countries: Belgium, France and Denmark. The approach identifies urban, architectural, social and environmental constants and variables of each country in order to better illustrate the reasons and nature of this shift of perception. First, the paper provides a comparative insight on legal contexts and urban policies that have favored or limited suburban development. This state of the art highlights how the increasing focus on sustainable development has introduced the concept of suburban transformation as being an integral part of the “urban sutainability” discourse. Finally, a number of case studies of retrofitting initiatives from the three countries are examined.