Circadian rhythms, or the body clock, confer temporal structure on human behavior and physiology to align homeostatic processes with anticipated changes in the environment. Disruption of these rhythms can influence health and well-being. Chronobiological research has often failed to consider how this temporal organization may be affected by sex. The few studies that do consider how these rhythms differ between sexes suggest a dimorphism that warrants further investigation. Recent findings from both humans and animal models illustrate how the systems that generate circadian rhythms diverge between the sexes, which has potential consequences for health and resilience to changes in sleep pattern.