Investigating how different forms of inequality arose and were sustained through time is key to understanding the emergence of complex social systems. Due to its long-term perspective, archaeology has much to contribute to this discussion. However, comparing inequality in different societies through time, especially in prehistory, is difficult because comparable metrics of value are not available. Here we use a recently developed technique which assumes a correlation between household size and household wealth to investigate inequality in the ancient Near East. If this assumption is correct, our results show that inequality increased from the Neolithic to the Iron Age, and we link this increase to changing forms of social and political organization. We see a step change in levels of inequality around the time of the emergence of urban sites at the beginning of the Bronze Age. However, urban and rural sites were similarly unequal, suggesting that outside the elite, the inhabitants of each encompassed a similar range of wealth levels. The situation changes during the Iron Age, when inequality in urban environments increases and rural sites become more equal.