Depressive disorder is one of the most common psychiatric disorders experienced by older adults. The misconception that “feeling sad is part of normal aging” contributes to the underdiagnosis and undertreatment of depressive disorders in the older population. According to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR), the category of depressive disorders includes disruptive mood dysregulation disorder, major depressive disorder, persistent depressive disorder, premenstrual dysphoric disorder, substance-/medication-induced depressive disorder, depressive disorder due to another medical condition, other specified depressive disorders, and unspecified depressive disorders. The term late-life depressive disorders applies to both older adults who are presenting with depressive disorder for the first time later in life (known as late-onset depressive disorder) and aging patients whose depressive disorders initially presented in earlier life, who now present with a recurrent episode. This chapter presents an overview of the symptomatology, evaluation, and treatment of depressive disorder in the older population.