This article contributes to the growing literature on colonial legacies influencing long‐term development. It focuses on Botswana, a case where the post‐independence diamond‐led economy has been considered an economic success story, despite its high levels of inequality. Here it is argued that this pathway of rapid resource‐driven growth combined with increasing socio‐economic inequality had already started during the time of the colonial cattle economy, and that this older case is equally relevant for understanding long‐term growth‐inequality trends in Botswana and other natural‐resource‐dependent economies. Six social tables, covering the period 1921 to 1974, are constructed using colonial archives, government statistics, and anthropological records. Based on the social tables, income inequality is estimated in the colonial and early post‐independence eras, capturing both the formal and informal sectors of the economy. The article demonstrates how the creation of a cattle export sector in the 1930s brought new opportunities to access export incomes, and how this led to a polarization in cattle holdings and increasing income inequalities. Further, with the expansion of colonial administration, government wages forged ahead, increasing income inequality and causing a growing income divide between public and private formal employment.