This study empirically investigated whether the Dangote Refinery represents industrial transformation or state capture in Nigeria’s downstream petroleum sector, using a convergent mixed-methods case study design covering 2020 to 2026. Nigeria historically spent an estimated $14 billion annually importing refined petroleum products, a structural weakness the refinery with a capacity of 650,000 barrels per day, exceeding the combined 445,000 bpd of all NNPC refineries was built to address. Quantitative data and qualitative documentary evidence drawn from institutional reports, policy documents, and media sources are triangulated to produce the findings. The refinery has generated approximately 29,000 jobs against NNPC’s 5,700, commands a 43.1 per cent market share, reduced petroleum import expenditure by 28.88 per cent between 2024 and 2025, and produced $5.85 billion in refined exports in 2025. However, concerns persist over preferential crude allocation, the March 2026 price increase made without prior regulatory notification, and the concentration of refining capacity within a single private entity. The study concludes that the refinery is driving measurable economic progress while simultaneously creating governance risks that demand stronger competition regulation, regulatory independence, and institutional transparency.