Global inequality has worsened over the past half century, with the real per capita income gap between the Global North and South quadrupling since the 1960s. The vast majority of gains from global economic growth have been captured by the rich, while the incomes of the majority remain too low to meet basic needs. At the same time, excess resource use in rich countries is driving ecological damage on a global scale. This chapter argues that rising inequality, persistent poverty and ecological breakdown are best understood as effects of imperialist dynamics in the world economy. Rich states use their geopolitical and commercial dominance to achieve a large net appropriation of resources and labour from the Global South through international trade and commodity chains. These patterns of appropriation make it difficult for developing countries to meet human needs, much less 'catch up' to richer countries. Achieving development in the twenty-first century while averting ecological breakdown will require strategies of decolonisation and convergence.