Purpose - Turkey has been rapidly urbanizing since the 1950s. In quantitative and qualitative meanings, the problem of housing is one of the most important subjects on Turkey's agenda. Increasing population, rapid cultural and economic transition and the dynamics of in-migration, changes in social life, consumption patterns and value systems have made a significant impact on housing demand and supply. If we try to realize a general analytical outlook to define the basic formal and informal categories that reflect specific values pertaining to housing typology of the twentieth century, it would be possible to make a classification under the following sub-titles: formal housing-row houses, separate houses, apartment blocks, social housing, mass-housing, luxury housing including gated communities; informal housing - squatter settlements/gecekondus, slums; inbetween -apartkondus, unpermitted constructions/building extensions. The paper aims to discuss these issues.