Patients admitted to an adult intensive care unit (ICU) are at risk of developing an acute condition known as ICU delirium, which can impact patients’ length of hospital stay and increase short term and 6-month mortality. The cause of ICU delirium is multifactorial, and lack of quality sleep is a known risk factor. Patients’ sleep in the ICU is frequently interrupted by clinicians involved in their care and equipment alarms. Sleep hygiene interventions to minimize these interruptions for the patient are one strategy to reduce the risk of ICU delirium. Examples of sleep hygiene interventions include eye masks, earplugs, and grouping patient care to minimize nighttime interruptions. The primary purpose of this thesis was to review the available evidence on non-pharmacological sleeping interventions and how they can prevent the development of ICU delirium in adults hospitalized with a critical illness. A secondary aim of this thesis was to study the impact of non-pharmacological interventions on sleep quality. Seven studies conducted in critical care units were included in this scoping review, which examined how non-pharmacological sleep hygiene interventions impacted both the prevention of ICU delirium, and sleep quality. Study results were analyzed to determine their effectiveness in relation to the two outcome measures. Although this review identified many benefits of non-pharmacological sleep interventions, the results on which are most effective in preventing delirium and improving sleep quality are inconclusive. Future research needs to be done to evaluate which sleep-promoting intervention(s) will benefit critical care patients most in preventing or lowering their risk of delirium. The feasibility of both health care staff consistently and effectively executing the intervention(s) outside of research conditions, and patient compliance to the interventions needs to be further studied. Additionally, there is a need for future studies measuring sleep quality as a result of sleep promoting interventions to be measured by PSG rather than subjective written/oral reports in order to obtain objective, reliable results.