This paper investigates the dynamic relationship between financial development and sectoral composition in emerging economies. Utilizing a panel ARDL model on a dataset of 45 emerging markets over the period 1995–2023, the study uncovers a robust empirical pattern: financial development is significantly associated with structural transformation, characterized by a declining share of agriculture and a corresponding increase in the share of industry—particularly services. The results also indicate the presence of bidirectional causality between financial development and the industrial and service sectors, suggesting a mutually reinforcing dynamic in the structural transformation process. However, the paper critically evaluates this general finding within the specific institutional context of Iran. It argues that under a state-dominated, bank-based financial system marked by financial repression and directed credit policies, the classical link between finance and structural change becomes distorted. The findings reveal that in such a setting, financial expansion does not necessarily lead to efficient resource allocation or support productive transformation and may even exacerbate structural rigidities. The paper concludes that for countries like Iran, quantitative financial expansion is insufficient. Rather, qualitative financial development—anchored in deep institutional and policy reforms—is a prerequisite for fostering a healthy and sustainable structural transition.