Marine oil pollution, with significant economic, environmental, and social impacts, requires an effective civil liability system. This study employs the Law and Economics approach, particularly Steven Shavell’s framework, to analyze and redesign Iran’s civil liability regime for oil pollution. Findings indicate four main deficiencies: absence of clear strict liability, low and unrealistic compensation limits, liability limited to shipowners, and lack of a supplementary financial mechanism. Comparative analysis of the international regime (CLC/FUND) and BRICS countries demonstrates that their relative success stems from systematic application and domestic adaptation of Shavell’s efficiency principles. Accordingly, the study proposes a three-tier model: (1) enacting a comprehensive maritime environmental liability law with conditional strict liability and dynamic compensation caps; (2) resilient institution-building including a national compensation fund and specialized arbitration board; and (3) phased and balanced accession to international conventions. Implementing this model can shift Iran’s system from reactive governance to proactive and resilient management of oil pollution risks.