The present thesis investigates the role that China has developed, taken, and enacted in its relationship with the Islamic Republic of Iran. In this work, the term “role” has a precise connotation that refers to the conceptualisation of international roles as defined and investigated by the so-called Role Theory of International Relations. In that context, this study has the modest theoretical objective of developing a two- dimensional interactionist model that identifies two fundamental dimensions – one structural and one ideational – constitutive of international roles. These two dimensions, by interacting together, also assure the performance and resilience of roles. In the case of China’s role in the partnership with Iran, the structural dimension is defined by the middle power-great power framework, which describes a (highly) asymmetrical relationship within which material and strategic interests are conceived and pursued. Vice versa, the ideational dimension is constituted by those identity concepts, historical references, and mutually understandable ideas that Chinese policymakers employ when interacting with their Iranian counterparts, which form altogether what can be described as a non-Western friendship. The interaction of these two dimensions defines the role that China has taken and enacted in its relationship with the Islamic Republic of Iran. The thesis presents it as that of the friendly stakeholder. As with every international role, the friendly stakeholder role has its dynamicity. In fact, it is subject to intra-role conflicts caused by Iran’s contestation or China’s underperformance. At the same time, the competition and confrontation with China’s other international roles cause role conflicts. Therefore, to understand how China has taken and enacted this role and managed the related conflicts, this study adopts a historical perspective on China- Iran relations, considering a timeframe from 1979 to 2015. Within these temporal boundaries, the thesis explores China’s role-taking and role performance in the relationship with Iran through four historical episodes: the 1979 Revolution in Iran, the Iraq-Iran War, China’s partial disengagement from cooperating with Iran in 1997, and the negotiations that led to the approval of the Joint Comprehensive Plan of Action, commonly known as the Iran Deal, in 2015. Each historical episode is located within the broader history of China’s foreign relations, emphasising the relationship with the United States as the most significant external intervening variable in China’s relationship with Iran. Ultimately, the objective of the thesis is threefold. Firstly, presenting the abovementioned theoretical model for the definition of international roles. Secondly, providing an original framework for understanding the bilateral dimension of Sino-Iranian relations. Lastly, helping to critically locate Iran within China’s Persian Gulf strategy, its relationship with the United States, and its rise as great power