Since the mid-twentieth century, the extraction and consumption of mineral aggregates (i.e., sand and gravel) has grown at a higher rate and on a larger scale than any other resource group, making it the largest mineral resource currently consumed globally. Although reliable data for extraction of mineral aggregates (referred to as sand extraction) are lacking, estimates suggest that current annual extraction is as high as 40 Gt. This has important social and ecological ramifications. The industry overall is also plagued by rampant illegality, a strong black market, and intense violence, and results in the generation of severe social and environmental injustices. Yet despite the wide-ranging impacts of sand mining, there continues to be an acute shortage of research on its extraction, impacts, and solutions for future resource governance. This article draws on the political ecology literature, utilizing the concept of the commodity frontier and the theoretical framework of extractivism whilst engaging with academic as well as non-academic, grassroots literature around sand mining, to introduce the concept of “sand frontiers”. Using the sand frontier as an analytical tool, four central questions are addressed, namely: 1) What are the drivers of expansion and intensification of sand frontiers? 2) What and where are the current and potential sand frontiers? 3) How is the forward movement of sand frontiers occurring? and 4) What are the identifiable socio-ecological transformations at these frontiers? In addressing these questions, the paper bridges research gaps around solutions to unsustainable sand extraction, using the lens of post-extractivism (PE) whilst continuing to put people living at sand frontiers at the centre of proposed solutions.