Public diplomacy is relatively a new field of practice and scholarship. As argued by many scholars, the realm of public diplomacy constitutes one of the most multidisciplinary concepts in the related scholarship. As already witnessed in its practices of a rather diversified manner, various disciplines have been utilized to offer workable theoretical and conceptual frameworks to public diplomacy. Building on this peculiarity, it has become an efficient tool to contribute to what is sought with it. Nevertheless, it is also argued that public diplomacy has mostly been mixed confusedly with other instruments, such as propaganda, public relations (PR), or psychological warfare. This derives from the fact that public diplomacy is in practice implemented for different purposes. Given all this, both scholars in academia and practitioners working in the related fields have sought to provide a variety of definitions of public diplomacy depending on its diverse purposes. In view of the foregoing, this chapter aims to focus on the concept as an instrument of foreign policy aimed at facilitating inter alia common perspectives and preventing misunderstanding among states. This indeed constitutes an urgent need for joint or at least concerted efforts which are increasingly felt for peace, security, stability, and prosperity, at both regional and global levels, under the current circumstances in the world affairs. Here, the chapter argues that public diplomacy can be instrumental in contributing to this quest. In this context, given its emphasis on socio-psychological and ideational factors which are predominantly influential in public diplomacy, without rejecting the realist parameters ruling the foreign polices of states, social constructivism as a theoretical tool can provide useful inputs to this role of public diplomacy as a foreign policy instrument. Based on this discussion the chapter ends with a proposal for Turkish foreign policy to utilize public diplomacy more in the Organization of Turkic States to promote common understanding among member and observer states as a means to foster inter-state relations.