Palestine has been witnessing enormous political, economical, social, cultural, urban…. transformation over the past 50 years resulted in changing the architectural residential designs from introverted into extraverted schemes. The latter are almost identical to all Palestine despite different climatic zones. Unlike traditional designs, contemporary architecture have, unfortunately, focused on issues such as cost, size, form and aesthetics rather than environmental, energetic, functional and socio-cultural values. Moreover, in contemporary housing, architects are more interested in interior environment than exterior. For all of these reasons, this new type of habitat extrovert is being questioned that justifying our study. This research focuses on the role of private outdoor space (traditional and modern) regarding spatial, environmental and human characteristics, How a courtyard is vital for sustainable housing in Palestine?To answer such questions, a state of the art of different benchmarks and factors involved in the housing design was presented in the first phase, the transformation it has been witnessing over time the hygrothermal quality and luminous environments. Particular attention was paid to the courtyard, a traditional form of outdoor space in the vernacular architecture and its functions. For contemporary dwelling this space takes mostly the form of a balcony or a loggia.In the second phase, the interrelationship between outdoor space and environmental quality of the Palestinian residences (traditional and contemporary) was discussed following two approaches: qualitative and quantitative. In the first one, an analytical and bioclimatic study of traditional dwellings in two cities (Jericho and Nablus) of two different climatic zones of Palestine was carried out. Then, the characteristics and the socio-environmental dimension in the contemporary housing design were investigated by conducting a questionnaire survey. For the second approach, in-situ measurements were carried out in a number of different habitat types to validate the outcomes of the first approach. Finally, in terms of conclusion, a set of design principles and recommendations were suggested that may improve the environmental quality in any future Palestinian residences.