Obstructive sleep apnea (OSA) is a common disorder that affects quality of life and is associated with comorbidities such as hypertension, atrial fibrillation, heart failure, coronary heart disease, type 2 diabetes mellitus, and stroke. OSA is characterized by a reduction or cessation of breathing during sleep, resulting in intermittent hypoxemia, autonomic fluctuation, and sleep fragmentation. The U.S. Preventive Services Task Force states that there is insufficient evidence to recommend routine screening for OSA in the absence of symptoms. OSA should be considered in patients with excessive daytime fatigue, unrestful sleep, persistent snoring, and nocturnal awakenings with gasping or choking. The STOP-BANG questionnaire is the most sensitive screening tool for OSA, and the diagnostic standard is polysomnography with an observed apnea-hypopnea index greater than 5 in the presence of symptoms or greater than 15 without symptoms. Home sleep apnea testing is a useful diagnostic option in patients who have symptoms consistent with moderate to severe OSA without significant cardiopulmonary comorbidities. Positive airway pressure, with a humidified nasal or facial mask, is the first-line treatment for adults with OSA. Weight loss is a beneficial adjunct to treatment through intensive lifestyle modification, medications, or bariatric surgery. Alternatives for patients intolerant of or nonadherent to positive airway pressure include changing the type of mask used, mandibular advancement devices, hypoglossal nerve stimulation, and other surgical interventions. Although many OSA therapies effectively improve daytime sleepiness and blood pressure, none have demonstrated a mortality benefit in randomized controlled trials.