The role of nongovernmental organizations is, in fact, the crystallization of the formal and organized presence of a country's people in foreign relations and the interactive process of the international community; hence friendship associations are among the most effective actors in the field of public diplomacy. Recent developments in the international arena illustrate the fact that the role of friendship associations and popular institutions and unofficial organizations in the global equilibrium is expanding, and along with that, the role of governments in this connection is shrinking. Since they are involved in two key areas, namely, relations between nations and the international environment, their field of activity is very broad and wide-ranging.Today, the mere pursuit of classical practices does not in any way meet the needs of modern diplomacy. Increasing the ability to access large volumes of information and the speed of their transmission to audiences around the globe has challenged foreign policy management by governments. Traditional hierarchical models, in the light of communication technology, unwittingly translate their role into complex and uncontrolled networks, and diplomacy can be interpreted in an interlocking mechanism of government, the media, and public opinion. On the other hand, undoubtedly, for a long time, the pre-emptive era of hard power has passed, and in the modern and postmodern world, what more than any other factor determines the direction and process of affairs in the relations between states, and in particular the nations, the power of thought, dialogue, Pen, mutual understanding, and human communication.Achieving political, security and economic goals has always been one of the main goals of countries in formulating and enforcing its foreign policy. In order to study these goals, countries have traditionally embraced diplomacy based on political, military, and economic approaches. Nevertheless, in the early years of the third millennium, relatively new approaches to diplomacy have been put forward, with more attention and more emphasis recommends strategies and tools for foreign policy officials and designers. This article aims to explore cultural diplomacy as the role of friendship associations in international relations and the impact of cultural factors on diplomacy and how to effectively use "soft power" in advancing diplomacy in countries.