Introduction: Carers of persons with dementia (PWD) experience high levels of burden and distress and may use criticism in an attempt to change the behavior of PWD and thereby reduce their distress. We hypothesized that carer distress and criticism would each have an impact on the psychological well-being of the PWD and examined whether criticism mediates the association between carer distress and PWD psychological well-being.; Methods: We recruited 61 persons with a recent diagnosis of dementia and their carer via U.K. dementia services and assessed at 2 time points 6 months apart. Carers completed questionnaire measures of burden and distress. We coded critical comments from a Camberwell Family Interview. PWD completed questionnaire measures of quality of life, depression, and anxiety. We conducted correlation, regression, and mediation analyses to explore the relationship between carer variables and PWD psychological outcomes and whether criticism mediated any relationship found.; Results: Carer distress, carer critical comments, and PWD anxiety and depression at 6-month follow-up were all significantly correlated. Baseline carer distress predicted poorer quality of life in PWD at 6-month follow-up. The number of carer critical comments significantly (p < .01) mediated the effect of carer distress on PWD quality of life.; Discussion: Interventions addressing carer burden and distress and offering coping strategies to help them to reduce criticism of the PWD would improve the quality of life of those affected by dementia.