Circadian rhythm disorders arise when the body’s internal clock fails to properly synchronize with the 24-h day, causing ongoing mismatches between biological sleep timing and desired schedules. Unlike temporary disruptions like jet lag, these disorders involve fundamental disruptions in the brain’s master clock, influenced by genetics, age, brain injuries, and environmental factors. Primary types include delayed sleep phase disorder (late sleep and wake times), advanced sleep phase disorder (sleeping and waking too early), non-24-h sleep-wake disorder (progressively shifting sleep times), and irregular sleep-wake rhythm disorder (disorganized and fragmented sleep patterns throughout the day and night). Effective treatment involves carefully timed interventions—such as light therapy, melatonin administration, and strict sleep routines—underscoring that these are medical conditions, not merely poor sleep habits.