The relationship between obesity and the onset of persistent daytime alveolar hypoventilation is known as obesity hypoventilation syndrome. This illness results from a complicated interaction between sleep-disordered breathing, reduced respiratory drive, and obesity-related respiratory impairment, and is associated with considerable morbidity and mortality. Extreme obesity has become far more common in the United States and other nations during the past three decades. The prevalence of OHS will inevitably rise considering the global obesity pandemic. When compared to people with sleep apnea, patients with OHS have a poorer quality of life, incur higher medical costs, and are more likely to develop pulmonary hypertension and die young. Even though this illness is associated with severe morbidity and mortality, it is commonly overlooked, and treatment is typically postponed. Clinicians need to keep a high index of suspicion since this syndrome carries a heavy burden of morbidity and mortality, which is reduced by early diagnosis and treatment. The definition and clinical presentation of OHS, a brief overview of its prevalence, a review of current understanding of pathophysiology, and discussion of recent developments in therapeutics will all be included in this review.