Adipose tissue is an important endocrine organ. It is involved in the regulation of energy metabolism by secreting factors (adipokines) that regulate appetite, food intake, glucose disposal, and energy expenditure. Many of these adipokines display profound day/night rhythms, and accumulating evidence links disruption of these rhythms to metabolic diseases such as obesity and type 2 diabetes. Here, we briefly present the circadian system, describe the development of white adipose tissue (WAT) and its depot-specific characteristics and innervation, we discuss energy storage in WAT and, lastly, review recent findings that link circadian rhythmicity to adipose tissue biology and obesity.