This article describes clinical approaches to assessing sleepiness. Subjective sleep scales are used in clinical settings but have significant limitations. Likewise, objective tools may have prohibitive expense, and practical administration considerations may prohibit regular use. Gold standard tests include the multiple sleep latency test and maintenance of wakefulness test. These studies are criticized for a variety of reasons but are useful in appropriate clinical context. New tools suggest novel ways to assess sleepiness and will likely be more prominent in clinical assessments over time. This article outlines subjective scales and objective tools and suggests situations where particular instruments may be appropriate.