Adipocyte development and differentiation have an important role in the aetiology of obesity and its co-morbidities(1,2). Although multiple studies have investigated the adipogenic stem and precursor cells that give rise to mature adipocytes(3-14), our understanding of their in vivo origin and properties is incomplete(2,15,16). This is partially due to the highly heterogeneous and unstructured nature of adipose tissue depots(17), which has proven difficult to molecularly dissect using classical approaches such as fluorescence-activated cell sorting and Cre-lox lines based on candidate marker genes(16,18). Here, using the resolving power of single-cell transcriptomics(19) in a mouse model, we reveal distinct subpopulations of adipose stem and precursor cells in the stromal vascular fraction of subcutaneous adipose tissue. We identify one of these subpopulations as CD142(+) adipogenesis- regulatory cells, which can suppress adipocyte formation in vivo and in vitro in a paracrine manner. We show that adipogenesis-regulatory cells are refractory to adipogenesis and that they are functionally conserved in humans. Our findings point to a potentially critical role for adipogenesis-regulatory cells in modulating adipose tissue plasticity, which is linked to metabolic control, differential insulin sensitivity and type 2 diabetes.