Obstructive sleep apnea (OSA) is highly prevalent and strongly associated with obesity. Mechanistic pathways include parapharyngeal fat deposition, reduced lung volumes, impaired upper-airway muscle responsiveness, and metabolic dysregulation, alongside a bidirectional relationship in which OSA can also contribute to weight gain. Weight-loss interventions consistently attenuate OSA severity: lifestyle programs yield meaningful reductions in apnea–hypopnea index and continuous positive airway pressure (CPAP) dependency; pharmacotherapies, particularly incretin-based agents, produce substantial improvements in respiratory and cardiometabolic outcomes; and surgical approaches achieve durable weight loss but variable effects on OSA remission. Despite these advances, most evidence derives from middle-aged males with obesity, limiting applicability to females, older adults, and individuals whose OSA is driven by non-obesity-related pathophysiology. Recognition of OSA heterogeneity underscores the need for integrated, phenotype-guided treatment strategies. This review aims to synthesize current evidence linking obesity and OSA and to critically evaluate weight-loss interventions alone and in combination with CPAP.
