The relationship between social capital and internal security has been shown in different studies. But is there a relationship between social capital and international security? To find the answer we dealt with two paths. The first, borrowing the concept of International Society examines the existence of social capital in this “society”. The role of trust and norms in international society in increasing cooperation and decreasing military conflicts is a manifestation of the impact of social capital on international security. The second path studies the role of social capital in international security through an intermediate variable; economic development. What has been shown here is a direct (but not necessarily linear) relationship between social capital and economic development on one hand and between economic development and International security on the other.