Cultural diplomacy, as a soft instrument of foreign policy, plays an important role in strengthening international relations. Ethnographic photography, with its capacity to document and represent cultural diversity, can serve as an effective tool for introducing national culture and identity to international audiences. This study examines the role of photography in Iran's cultural diplomacy by investigating the ethnographic photographs of Nasrollah Kasraian. It addresses two research questions: (1) What role does Iranian photography play in representing and communicating Iran's cultural characteristics internationally? (2) How can Kasraian's ethnographic photographs function as an instrument of cultural diplomacy?

The study is based on Joseph Nye's theory of soft power, which provides the conceptual framework for analyzing photography as a medium of cultural diplomacy. Data were collected through library and field research, and five ethnographic photographs by Kasraian were purposively selected for qualitative analysis based on their representation of Iran's ethnic diversity and their circulation in international contexts.

The findings demonstrate that Iranian documentary photography, particularly Kasraian's ethnographic works, has considerable potential to support cultural diplomacy. Through authentic representations of cultural diversity, rituals, livelihoods, handicrafts, and the everyday lives of ethnic communities, these photographs communicate Iranian culture while functioning as valuable visual and historical documents. They also contribute to cultural attraction, promote intercultural understanding, challenge stereotypical representations of Iran, and present a more nuanced image of Iranian society. These characteristics closely correspond to the principal components of Nye's soft power theory, including attraction, credibility, and cultural influence.

The study concludes that ethnographic photography extends beyond its documentary function and serves as an effective instrument of cultural diplomacy by enhancing Iran's soft power, strengthening its international image, and fostering cross-cultural dialogue. Kasraian's photographs illustrate how visual representation can become a strategic cultural resource for communicating national identity and cultural values in the international arena