The purpose of this study was to compare neuropsychiatric symptoms (NPS) among people with common dementias and equip interdisciplinary clinicians and health services planners with large-sample data necessary to plan care for patients and families. We analyzed selected variables from baseline assessments of older adults with dementia of one or more etiologies (N = 3,768) from the National Alzheimer's Coordinating Center data repository. Dementias included Alzheimer's disease (AD), Lewy body dementia (DLB), behavioral variant frontotemporal dementia (bvFTD), and vascular dementia (VaD). We compared the prevalence of four NPS clusters (agitation/aggression, depression/dysphoria, anxiety, irritability/lability) across dementia etiologies and stages using logistic regression and AD as the reference group. NPS profiles differed significantly across dementia types and stages. Compared with primary AD, DLB was associated with greater odds of depression/dysphoria (OR = 1.68, 95% confidence interval [CI] 1.28, 2.20) and anxiety (OR = 1.80, 95% CI 1.37, 2.36), with similar findings when DLB was diagnosed in combination with AD (depression/dysphoria: OR = 1.79, 95% CI 1.11, 2.89; anxiety: OR = 1.88, 95% CI 1.17, 3.02). Primary bvFTD was associated with greater odds of agitation/aggression (OR = 1.59, 95% CI 1.17, 2.18). The prevalence of anxiety and irritability/lability was highest in moderate stages of dementia, and agitation/ aggression was most prevalent in severe dementia. Differential diagnosis and staging of dementias and inclusion of single and overlapping etiologies is important for planning and implementing appropriate strategies to anticipate, report, and intervene with key NPS that complicate home and health care.