Cultural diplomacy constitutes a critical dimension of contemporary international relations, fostering mutual understanding and cooperation by enabling the exchange of ideas, values, and cultural elements among nations. Within this context, parliamentary diplomacy emerges, advancing cultural objectives through the activities of parliamentary assemblies. This study explores the contributions of the European Union’s parliamentary assemblies to the promotion of cultural diplomacy by analyzing initiatives such as the Lux Prize, the European Year of Cultural Heritage, and collaborative efforts with international cultural organizations. The research employs theoretical frameworks developed by Cummings (2003) and Weisglass and de Boer (2007) alongside a SWOT analysis to assess the effectiveness of these efforts. Findings reveal that EU parliamentary assemblies, through their institutional structures and strategic partnerships, have successfully established platforms for intercultural dialogue and bolstered the EU’s soft power. However, the study also identifies key challenges, including resource limitations, restricted public engagement, and predominantly top-down approaches. The analysis highlights that the EU’s cultural diplomacy, operating at the nexus of parliamentary initiatives and global diplomatic efforts, has created substantial opportunities for enhancing cultural interactions and fostering international collaboration. Drawing on these insights, the study recommends that the Islamic Republic of Iran develop a structured framework inspired by the EU’s experiences to harness parliamentary diplomacy for promoting cultural heritage and strengthening global engagement.