Each day, the gastrointestinal tract encounters an influx of microbial and nutrient-derived signals and its physiological activities often adhere to a circadian rhythm. As such, group 3 innate lymphoid cells (ILC3s) that reside in the intestinal mucosa must function within a highly dynamic environment. In this Progress article, we highlight a series of recent reports that have characterized the circadian clock in ILC3s. We discuss how these studies have illustrated the roles of environmental cues and clock genes in regulating ILC3 biology and consider the implications for intestinal immunity.