Disturbed sleep affects multiple aspects of an individual's life, including daytime activity, social interactions, mood, and quality of life. Individuals with mental health issues often experience disturbed sleep, and particular attention must be given to underlying lifestyle, family issues, and health problems that may perpetuate a sleep complaint. In addition to patients' medical conditions, clinicians should ask patients about their sleep-wake patterns and medication use, since these factors contribute to disturbed sleep and adverse mental health outcomes. This article provides advanced practice nurses with a brief sleep assessment guide for use in psychiatric practice with adults or children.