The aim of this study is to explore the active role of the public libraries in the Sultanate of Oman in building social capital by exploring the reality of the public libraries in Oman and their ability to build social capital and learning about the activities and services provided which can contribute in building social capital, identify the awareness of employees of these libraries about the concept of social capital and the use of library resources to achieve that. Also, to raise awareness level of the concept of social capital among members of civil society and to encourage them to participate actively in communication with public libraries for building mutual trust. This study is based on the qualitative approach, being the most appropriate for the nature of this study and achieving its objectives. It is based on a thorough, accurate and detailed examination and a full understanding of the problem of the study and its interpretation of dimensions. The researcher used a Semi structured interview tool, and document analysis to gather data. Two public libraries in the Sultanate have been covered, the General Knowledge Library and the Sultan Qaboos Grand Mosque Library. The researcher has conducted 20 direct interviews, 3 interviews were done for staff and 7 for users in each library. The results of the study concluded that the level of awareness of employees and users of the concept of social capital in the public libraries in the Sultanate of Oman ranges between the middle and high level in the two study sample libraries. Also the results of the study revealed the role of public libraries in embracing various governmental and professional institutions through the activities, services, programs and training workshops offered by libraries, which in turn reflect the size of relations and institutional linkage between libraries, institutions and other organizations in civil society, to achieve their objectives and functions to serve civil society and develop their skills and talents to participate in economic development. The study also reflected the value of the library to the beneficiary through its continuity and active participation, which deepened the trust, respect and affection between the beneficiary and the staff. This gave the library a public value that played a major role in the formation of social capital in these libraries. Despite the different of capacities and resources, these libraries defend their existence and struggle to appear as service organizations in Omani civil society with a significant role. The study concluded with several recommendations, including the planning to build public libraries, providing them with facilities. Focus on the need to place specialists or graduates of library departments or information studies in the hierarchy of the organizational structure of public libraries, as well as the include of the social capital as a basic requirement in the strategies and plans of government ministries and non-governmental organizations to benefit from the different experiences in the Sultanate. In addition, raising awareness of the concept of social capital among members of civil society, strengthening social relations using social media; for the development of social capital.