Purpose of Review <p>This review discusses the major factors that challenge circadian rhythms in the military operational environment and describes recent efforts to mitigate the effects of circadian misalignment.</p> Recent Findings <p>The biological clocks of military service members are challenged by multiple factors: shiftwork, unpredictable work schedules, excessively long work hours, and their age-dependent sleep needs. We describe recent efforts to mitigate the effects of circadian misalignment by classifying them into seven groups: fixed (circadian) watchstanding schedules, improvements to sleep-related habitability, light management, biomathematical models, real-time monitoring of military members’ sleep/wake patterns, training, and policy/regulations.</p> Summary <p>The issue of circadian desynchrony is part of the bigger problem of fatigue in the operational military environment. Even though none of the described mitigation efforts, on their own, is sufficient to remedy circadian disruption, when combined in a systematic approach, these efforts can benefit the military by contributing to reducing fatigue.</p>