Effective participation of the private sector in policymaking for Iran’s international transport is constrained by institutional, structural, cultural, economic, and political barriers that diminish sectoral influence and institutional credibility. Using a mixed methods design under a pragmatic paradigm, the qualitative strand employed thematic analysis of fourteen semi‑structured interviews with experts, applying Braun and Clarke’s six‑phase model to synthesize 438 initial codes into four themes: (1) Administrative and managerial inefficiencies, including absence of systemic approaches, regulatory instability, overlapping responsibilities, and weak organizational cohesion; (2) Cultural, social, and sectoral issues, such as prioritizing narrow interests over national concerns, intra‑organizational conflicts, declining legitimacy, reduced participation, and financial dependence; (3) Economic barriers like non‑developmental asset accumulation, lack of financial transparency, and conflicts of interest; and (4) Political obstacles involving blurred responsibilities, incomplete delegation, and overlap of state regulatory and enterprise roles. In the quantitative strand, data from a 17‑item Likert survey were analyzed via statistical tests and exploratory factor analysis, yielding four factors explaining over 60% of variance. Results showed strong convergence between qualitative themes and quantitative factors, indicating that bureaucratic inefficiency, organizational fragmentation, limited expert capacity, and the government’s dual role have the greatest negative effects. Integration validated a collaborative governance model and emphasized policy measures including regulatory stability, joint committees, specialized training, electoral system reform, and strategic legal mechanisms to establish a sustainable, participatory framework capable of enhancing Iran’s role in international transport corridors.