Sleep abnormalities are clearly recognized as distinct clinical symptom of concern in neurodegenerative disorders. Appropriate management of sleep related symptoms has a positive impact on the quality of life of patients with neurodegenerative disorders. This review provides an overview of mechanisms that are currently being considered that tie sleep with neurodegeneration. It appraises the literature regarding specific sleep changes among common neurodegenerative diseases with a focus on Alzheimer’s disease and synucleinopathies (i.e., Parkinson’s disease, dementia with Lewy bodies, multiple system atrophy) that have been better studied. Sleep changes may also serve as markers to identify patients in the preclinical stage of some neurodegenerative disorders. A hypothetical model is postulated founded on the conjecture that specific sleep abnormalities, when noted to increase in severity beyond that expected for age, could be a surrogate marker reflecting pathophysiological processes related to neurodegenerative disorders. This provides a clinical strategy for the screening of patients in the preclinical stages of neurodegenerative disorders to enable therapeutic trials to establish efficacy of neuroprotective agents to prevent or delay the development of symptoms and functional decline. It is unclear if sleep disturbance directly impacts neurodegenerative processes or is a secondary outcome of neurodegeneration; this is an active area of research. The clinical importance of recognizing and managing sleep changes in neurodegenerative disorders is beyond doubt.