White adipose tissue (WAT) serves to store energy in the form of triglyceride while also coordinating systemic metabolic function through the elaboration of a wide variety of hormones, collectively called ‘adipokines’ [1]. In the setting of unchecked overnutrition, WAT expands dramatically to accommodate excess calories, but eventually becomes dysfunctional, leading to the development of insulin resistance and type-2 diabetes (T2D) [1]. Understanding how WAT performs its normal physiological duties and how this goes awry in overnutrition are major goals of the effort to combat obesity and T2D. WAT can appear to be a simple aggregation of lipid-filled adipocytes, at least upon cursory histological examination. In fact, we now realize that the composition of WAT is complex, heterogeneous, and dynamic (Figure 1). It is complex, because there are many cell types that comprise WAT beyond adipocytes, including vascular, immune, and stromal cells, among others. It is heterogeneous, in that the composition of WAT depends upon the depot, and even which part of the depot, from which it is taken. It is dynamic, because the composition of WAT, even within a specific depot, can change dramatically under different conditions, such as overnutrition or cold exposure. Exploring the composition of WAT at single-cell resolution is unusually difficult relative to other tissues, because adipocytes are large and fragile, and do not survive the shear stresses within the microfluidic devices used in single-cell RNA-seq (scRNA-seq) approaches. This problem has been dealt with in several ways. Initial studies focused on the nonadipocytes within fat pads following their isolation using mechanical dissociation. Later, the advent of single-nucleus RNA-seq (sNuc-seq) enabled examination of the adipocytes themselves. In addition, newer spatial transcriptomic methods allow examination of WAT at near-single-cell resolution in situ. In this review, we briefly describe some of the key insights into the nonadipocyte populations of WAT, and then focus on newly discovered heterogeneity of the adipocytes themselves.