Hydrocephalus is a medical condition resulting from abnormal accumulation of cerebrospinal fluid (CSF) in the cerebral ventricular system due to improper reabsorption or obstruction of CSF flow that can result from multiple etiologies. Normal pressure hydrocephalus (NPH) is the most common type of hydrocephalus and preferentially affects adults over age 60. NPH results from a gradual accumulation of excess CSF within the ventricles, leading to progressive ventricular enlargement, which can shift brain parenchyma due to the expansion of the ventricles. Clinically, NPH may present with heterogeneous physical, cognitive, and neuropsychiatric symptoms, although it is classically associated with a symptom triad consisting of progressively impaired ambulation, urinary incontinence, and cognitive dysfunction/altered mentation. Cognitive dysfunction is diverse and can involve deficits in global cognition, attention/working memory, executive functions, memory, visuospatial abilities, and/or psychomotor speed. Neuropsychiatric/behavioral sequelae, including psychomotor retardation and slowing of mentation, depression, lethargy/drowsiness, diminished volition/amotivation, apathy, and affective blunting, are also common. Unlike other neurodegenerative conditions, NPH is considered a “reversible dementia,” meaning that physical and cognitive symptoms can be mitigated, though often incompletely, by early identification and intervention. This chapter will differentiate NPH from hydrocephalus due to other etiologies, contrast established international guidelines for diagnosis, review NPH pathophysiology, epidemiology, and core symptoms/clinical presentation, identify common cognitive and neuropsychiatric changes, and describe NPH as a variably modifiable cause of dementia with neurosurgical intervention.