Despite its fossil fuel resources and renewable energy potential, Iran faces electricity supply imbalances and difficulties in transitioning toward a sustainable power system. Its rank of61and BBD performance profile (high security, medium equity, and very low sustainability) in the2024World Energy Trilemma Index indicate a gap between energy system objectives and performance. This study examines how transition lock-in in Iran’s electricity system emerges and persists, focusing on the interaction of constraining contexts, dominant actors, and governance outcomes. Using a qualitative approach and thematic analysis, the study analyzes data from 22semi-structured interviews with electricity sector experts. The findings identify five constraining contexts—historical-institutional, macroeconomic, ecological, ideological-cultural, and social—which interact with seven groups of dominant actors, including the Ministry of Energy and Parliament, to produce 17 governance outcomes. Key outcomes include dependence on natural gas for electricity generation, fuel supply constraints, rolling blackouts, mandatory industrial load shedding, administered pricing, infrastructure deterioration, a low share of low-carbon generation, mazut combustion, and the degradation of natural resources to address short-term crises. These interconnected outcomes affect supply security and quality, energy equity, and environmental sustainability. Two central mechanisms underpin this condition: the dual role of government in reproducing existing rules while facing constraints on reforming them, and the mediation of sanctions through institutional structures and dominant actor networks. The study therefore emphasizes a system-oriented approach linking renewable energy development with storage and grid flexibility, revised investment and modernization priorities, energy democracy through prosumer participation, independent review of decision-making, and a transition pathway tailored to Iran’s resource endowments.