Background: Delirium is a rare but clinically significant complication of opioid withdrawal that remains poorly characterized in the literature. While classical withdrawal symptoms are well recognized, atypical presentations such as delirium are less frequently reported and often challenging to diagnose due to symptom overlap and heterogeneity of withdrawal syndromes. Methods: In this systematic review, we systematically analyzed available case reports and case series describing delirium precipitated by spontaneous opioid withdrawal, tapering, or antagonist-induced withdrawal. Twelve papers met inclusion criteria, comprising a total of fifteen case reports. Results: Most patients (n = 15) developed delirium within hours to days of withdrawal onset, often with fluctuating consciousness, disorientation, perceptual disturbances, and psychomotor changes. Reported risk factors included psychiatric comorbidity (major depressive disorder, anxiety disorder), concomitant use of psychotropic medication, rapid detoxification protocols, and potential exposure to adulterated substances. Management strategies varied but generally involved supportive care, benzodiazepines, antipsychotics, or reinstatement of opioid agonists. Conclusions: The findings highlight the need for heightened clinical awareness, careful differentiation from other withdrawal-related neuropsychiatric states, and systematic exclusion of organic etiologies. Despite the increasing number of patients affected by OWS, the knowledge available to date is based on case reports and a small case series, making it impossible to critically assess the prevalence or identify risk factors. Future research should aim to identify risk factors, optimize treatment, and explore novel diagnostic approaches, including AI-driven monitoring and connectomic analyses, to improve early detection and therapeutic outcomes in opioid withdrawal-associated delirium.