Apathy is common across various neurological disorders. However, apathy is one of the earliest and probably the most persistent neuropsychiatric symptoms in patients with Alzheimer's disease. It is defined as lack of motivation and is manifested by diminution of goal-directed cognition and behavior. Apathy is linked with a faster progression of cognitive, functional, and emotional impairment. It is also associated with decreased insight. As a result, patients with apathy rely on caregivers to provide more care that results in increased stress for caregivers. Neuropathological changes in Alzheimer's disease may result in apathy by affecting the orbitofrontal and anterior cingulate circuits. Although apathy is increasingly recognized in patients with neuropsychiatric symptoms, no official diagnostic classification systems offer a definition of apathy. In this review, neuropathological correlates, neuroimaging, diagnosis, caregiving issues, and treatment are briefly discussed for clinicians who care for persons with Alzheimer's disease.