Background: The study aimed to compare neuropsychiatric symptoms (NPS) in people with early-onset Alzheimer’s disease (EOAD) and late-onset AD (LOAD). Methods: Fifty-six participants with LOAD and 24 participants with EOAD having mild dementia were assessed for NPS for their frequency, severity, and caregiver distress as measured by Neuropsychiatry Inventory (NPI) along with assessments of cognition and functional dependence. Results: Participants with EOAD and LOAD were not significantly different for total NPI score ( P = .057). Early-onset Alzheimer disease had greater prevalence of all the NPS except apathy. Participants with EOAD were significantly worse on anxiety ( P = .03), irritability ( P = .01), and sleep ( P < .01) subscales and their carers significantly more distressed by their irritability ( P = .002) and sleeping patterns ( P = .005). Regression analysis showed that higher NPI score was associated with longer duration of illness in EOAD and higher functional dependence in LOAD. Conclusions: The NPS severity was similar between EOAD and LOAD although EOAD had higher symptom prevalence and carer distress.