Late-life depression is a common and debilitating condition affecting many older adults and is expected to increase with the aging global population. Often underdiagnosed and undertreated—especially among minorities—it is linked to higher morbidity, mortality, and a greater risk of suicide. Its multifactorial etiology includes biological factors like vascular diseases, inflammation, and neurodegeneration; psychological factors such as stress and cognitive distortions; and social factors involving isolation and poor support. Clinically distinct from early-onset depression, it often presents with somatic complaints, anxiety, cognitive impairments, and executive dysfunction, sometimes mimicking dementia (pseudodementia). Effective treatment of late-life depression requires an extensive methodology that integrates non-pharmacological approaches—such as psychotherapy, electroconvulsive therapy, transcranial magnetic stimulation, and aerobic exercise—alongside pharmacological interventions, typically involving antidepressants and augmentation strategies. Managing late-life depression is essential for reducing disability and enhancing the emotional, social, and physical well-being of older adults.