Secondary mania, also known as secondary bipolar disorder, is a mood disorder characterized by episodes of mania or hypomania that are attributed to an identifiable physical or medical condition rather than primary psychiatric origins. This condition can arise due to various factors, including neurological disorders, systemic illnesses, medications, or substance abuse. Secondary mania often presents diagnostic and therapeutic challenges as a comprehensive evaluation is required to identify the underlying cause. Understanding the pathophysiology, clinical manifestations, and treatment strategies for secondary mania is crucial for effective management. This chapter explores the etiology, diagnostic criteria, differential diagnosis, and evidence-based treatment approaches for secondary mania, highlighting the importance of interdisciplinary collaboration in managing this complex disorder.