Xerostomia (dry mouth) is a common complaint with widespread implications such as impaired quality of life, oral pain, and numerous oral complications. There are a variety of salivary and nonsalivary causes of xerostomia, the most frequent being medication side effects and systemic disorders. A systematic approach should be employed to determine the etiology of this condition, with distinctions made between patients with subjective complaints of xerostomia alone and those with measurable salivary gland dysfunction. Management is multidisciplinary and multimodal. This review summarizes the current literature on the etiology, diagnosis, and complications of xerostomia, and on the management of patients with xerostomia.