This thesis addresses the problem of territorial development in rural touristic areas and the role of social capital to support this development. The theoretical framework of this research is illustrated by the study of two touristic territories in Lebanon: Aley and Mzaar, which exist in rural mountainous regions. The main goal of this study was to examine the effect of social capital on territorial development as well as on the living standards of the inhabitants of touristic territories. For this purpose, we first constructed a statistical model that represents the relationship between the different forms of social capital and the living standards of individuals. And second, we compared the levels of tourism development between the two territories with the levels of social capital they possess, this comparison allowed us to build a conclusion about the effect of social capital on the development of tourism at territorial levels. Our analysis of the effect of social capital on development differentiates its structural forms (bonding, bridging and linking) from its functional forms (citizenship and trust). The purpose of this decomposition is to find out if it is precisely the structural forms of social capital (networks in these forms) that explain this difference in development, or whether it is the functional aspects that affect more strongly the difference. In conclusion of this research, we propose a SWOT study that shows the strengths, the weaknesses, the opportunities and the threats of development in the territories of Mzaar and Aley. This analysis allows us to suggest some procedures that can be implemented as part of a development strategy for these two territories. These procedures aim to make use of the forces, to offset weaknesses, to avoid threats, and to seize opportunities. The added value of our work is that it goes beyond the study of social capital as a global concept; rather it seeks to explore the various components and forms of this capital and their impact on the level of development of touristic areas in Lebanon (a developing country). This allows us to find out if there is a difference in terms of the effect of social capital on development between poor countries such as Lebanon and rich countries like France and Italy.