•Classification framework of secondary resources was applied to aluminum.•Global secondary aluminum reserves were estimated 413 million tonnes.•Considerable amount of secondary aluminum are accumulated in landfill sites. A classification framework of the secondary resources was applied to evaluate the framework’s applicability and to assess secondary aluminum reserves for 19 countries. Estimated amounts of secondary aluminum reserves in 2010 were 85 million tonnes in the United States, 65 million tonnes in China, 29 million tonnes in Japan, and 413 million tonnes globally. For the United States, its secondary reserves are larger than its primary reserves, although the global primary reserves (28,000 million tonnes) are much larger than the estimated secondary reserves. Considerable amounts of secondary aluminum resources are accumulated in landfill sites. Understanding the sizes of primary and secondary aluminum reserves enables us to extend knowledge of efficient raw material sourcing from a narrow perspective of primary reserves alone to a broader perspective of both primary and secondary reserves, and to progress towards sustainable resource management.