The circadian clock plays a critical role in coordinating energy metabolism across tissues, including brown adipose tissue (BAT), a major site of nonshivering thermogenesis. This study aimed to elucidate the cell-autonomous role of the peripheral circadian clock in brown adipocyte thermogenesis using an in vitro model independent of extrinsic cues. Primary brown adipocytes were differentiated from the stromal vascular fraction of interscapular BAT isolated from C57BL/6J mice. An in vitro model o