This study investigates the effect of organizational social capital (OSC) in non-profit organizations on communal social capital (CSC) in the communities where these organizations operate. The study has two goals: First, to theoretically establish rational for the relationship between internal organizational social capital (IOSC) and external organizational social capital (EOSC), especially with relation to public administration agencies in liberal democracies where social capital plays a major role in public policy. Second, to empirically analyze the reciprocal relationship between EOSC, CSC, and IOSC which constitutes an important product of the optimal public administration model in modern nations. A theoretical model was developed to study these relations and suggest several hypotheses. The field study was conducted in 72 community centers operated by the Israel Association of Community Centers. Participants were 1,015 employees (72 general managers, 501 middle managers, and 442 line employees) and 1,816 community members. The findings demonstrate partial support for the relationship between IOSC and EOSC and indicate that IOSC has a moderating influence on the relationship between the EOSC and CSC. Implications and suggestions for future studies in public organizations and their social and administrative sphere are highlighted.