Objective: To estimate the additional societal costs for people living with dementia (PwD) with agitation in home care (HC) and institutional long-term care (ILTC) settings in 8 European countries.; Design: Cross-sectional data from the RightTimePlaceCare cohort.; Setting: HC and ILTC settings from 8 European countries (Estonia, Finland, France, Germany, Netherlands, Spain, Sweden, and England).; Participants: A total of 1997 PwD (1217 in HC group and 780 lived in an ILTC) and their caregivers.; Main Outcome Measures: Medical care, community care, and informal care were recorded using the Resource Utilization in Dementia (RUD) questionnaire. Agitation was assessed based on the agitation symptoms cluster defined by the presence of agitation and/or irritability and/or disinhibition and/or aberrant motor behavior items of the Neuropsychiatric Inventory Questionnaire (NPI-Q).; Results: Total monthly mean cost differences due to agitation were 445€ in the HC setting and 561€ in the ILTC setting (P = .01 and .02, respectively). Informal care costs were the main driver in the HC group (73% of total costs) and institutional care costs were the main driver in the ILTC group (53% of total costs). After adjustments, the log link generalized linear mixed model showed an association between agitation symptoms and an increase of informal care costs by 17% per month in HC setting (P < .05).; Conclusion: This study found that agitation symptoms have a substantial impact on informal care costs in the community care setting. Future research is needed to evaluate which strategies may be efficient by improving the cost-effectiveness ratio and reducing the burden associated with informal care in the management of agitation in PwD.