The capacity to handle money and personal finances is crucial for living independently. Cognitive decline can lead to financial mismanagement (e.g., forgetting to pay bills, overspending) and exploitation (e.g., falling for financial scams). While greater susceptibility to financial mismanagement and exploitation is commonly reported by carers of people with dementia, objective neuropsychological measures of these financial skills are scarce. It is also unclear whether profiles of change in financial skills vary across different stages and subtypes of dementia. A normative sample of 112 healthy controls and individuals with mild cognitive impairment (MCI; n = 16), Alzheimer's disease (AD; n = 7) or behavioural-variant frontotemporal dementia (bvFTD; n = 18) completed a novel neuropsychological Test of Financial Skills (TOFS), which assessed performance across three key areas: everyday financial tasks, susceptibility to financial scams and financial goal planning. For all patients and controls, measures of dementia severity (Clinical Dementia Rating Scale) and general cognition (Addenbrooke's Cognitive Examination, 3rd Ed.) were also collected. Relative to controls, AD and bvFTD patients showed lower overall performance on the TOFS, whereas MCI patients did not differ significantly from controls. While AD and bvFTD patients showed similar levels of impairment on everyday financial tasks and financial goal planning, bvFTD patients performed significantly worse on the financial scams subtest. Across all participants, lower TOFS performance was associated with greater dementia severity and cognitive impairment. Our results are consistent with previous studies of carer-reported changes in financial mismanagement and exploitation in people with dementia. Notably, we found important differences in the areas of financial skills impacted by different stages and subtypes of dementia. These findings provide novel insights into the different factors that contribute to deficits in financial skills in people with dementia, highlight the importance of objective neuropsychological assessments in this area, and open avenues for targeted financial support strategies.