Background Alzheimer disease (AD) is more prevalent in African American (AA) and Hispanic White (HIW) compared to Non‐Hispanic White (NHW) individuals. Similarly, neuropsychiatric symptoms (NPS) vary by population in AD. This is likely the result of both sociocultural and genetic ancestral differences. However, the impact of these NPS on AD in different groups is not well understood. Methods Self‐declared AA, HIW, and NHW individuals were ascertained as part of ongoing AD genetics studies. Participants who scored higher than 0.5 on the Clinical Dementia Rating (CDR) Scale (CDR) were included. Group similarities and differences on Neuropsychiatric Inventory Questionnaire (NPI‐Q) outcomes (NPI‐Q total score, NPI‐Q items) were evaluated using univariate ANOVAs and post hoc comparisons after controlling for sex and CDR stage. Results Our sample consisted of 498 participants (26% AA; 30% HIW; 44% NHW). Overall, NPI‐Q total scores differed significantly between our groups, with HIW having the highest NPI‐Q total scores, and by AD stage as measured by CDR. We found no significant difference in NPI‐Q total score by sex. There were six NPI‐Q items with comparable prevalence in all groups and six items that significantly differed between the groups (Anxiety, Apathy, Depression, Disinhibition, Elation, and Irritability). Further, within the HIW group, differences were found between Puerto Rican and Cuban American Hispanics across several NPI‐Q items. Finally, Six NPI‐Q items were more prevalent in the later stages of AD including Agitation, Appetite, Hallucinations, Irritability, Motor Disturbance, and Nighttime Behavior. Conclusions We identified differences in NPS among HIW, AA, and NHW individuals. Most striking was the high burden of NPS in HIW, particularly for mood and anxiety symptoms. We suggest that NPS differences may represent the impact of sociocultural influences on symptom presentation as well as potential genetic factors rooted in ancestral background. Given the complex relationship between AD and NPS it is crucial to discern the presence of NPS to ensure appropriate interventions. Key points Our study sought to determine if there are differences in neuropsychiatric symptom prevalence, as measured by the Neuropsychiatric Inventory Questionnaire (NPI‐Q), among self‐declared African American (AA), Hispanic, and Non‐Hispanic White (NHW) individuals with Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). While the prevalence of several NPI‐Q symptoms was consistent across the three groups our Hispanic participants showed a greater overall burden of neuropsychiatric symptoms—especially anxiety and mood symptoms (i.e., Anxiety, Depression, Apathy, and Irritability items). By contrast, African Americans reported significantly more behavioral problems as reflected on the Disinhibition and Elation items. The variability in the prevalence of neuropsychiatric symptoms among different populations (e.g., mood and anxiety symptoms in HIW) represents both underlying genetic factors rooted in ancestral background as well as sociocultural influences on the measurement and reporting of NPS.