||PURPOSE: Although sleep is important for healing, sleep deprivation is a major concern for patients in hospitals. The purpose of this review is to consolidate the observational and interventional studies that have been done to understand exogenous, non-pharmacological strategies for improving sleep in hospitals. DATA SOURCES: We searched Medline, CINAHL, PsycINFO and the Web of Science databases for peer-reviewed articles published between 1970 and 2015 in English. STUDY SELECTION: A title review of 13,113 articles from four databases resulted in 783 articles that were further culled to 277 based on a review of the abstracts. The net result after reading the articles and a hand search was 42 articles. DATA EXTRACTION: From each article we recorded the independent variables, methods used for measuring sleep and specific sleep outcomes reported. RESULTS OF DATA SYNTHESIS: Noise is a modifiable cause of some sleep disruptions in hospitals, and when reduced can lead to more sleep. Earplugs and eye masks may help, but changing the sound and light environment is more effective. Calming music in the evening has been shown to be effective as well as daytime bright light exposure. Nursing care activities cause sleep disruption, but efforts at limiting interventions have not been demonstrated to improve sleep conditions. CONCLUSION: The research is hard to consolidate due to the multitude of independent variables and outcome metrics, but overall points to the potential for making meaningful improvements in the quality of patient sleep.