Alzheimer's disease (AD) is increasing in prevalence and has a significant impact on caregivers and the healthcare system. One of the many physiologic process affected by AD is the circadian system, with disruption reflected in abnormalities of the sleep-wake cycle. This interaction is bidirectional, with circadian and sleep disruption influencing disease progression. Understanding the bidirectional relationship between AD and circadian disruption may allow for earlier recognition of the potential to develop dementia as well as improved targeted approaches for therapy. Therapies including melatonin and bright light therapy may be advantageous in improving sleep and circadian rhythms and preventing the progression of disease. However, unfortunately, these modalities are not curative, and additional research is needed to improve treatment options for these individuals.