Background and Objectives Person-centred care is the gold standard of care for people living with dementia, yet few systematic reviews have detailed how it is delivered in practice. This mixed-methods review aimed to examine the delivery of person-centred care, and its effectiveness, for people living with dementia in residential aged care. Research Design and Methods A systematic review and meta-analysis. Eligible studies were identified across four databases. Quantitative and qualitative studies containing data on person-centred care delivered to people with dementia living in residential aged care were included. Meta-analysis using a random effects model was conducted where more than three studies measured the same outcome. A narrative meta-synthesis approach was undertaken to categorise verbatim participant quotes into representative themes. Risk of bias was undertaken using quality appraisal tools from the Joanna Briggs Institute. Results Forty-one studies were identified for inclusion. There were 34 person-centred care initiatives delivered, targeting 14 person-centred care outcomes. Three outcomes could be pooled. Meta-analyses demonstrated no reduction in agitation (standardised mean difference -0.27, 95% CI -0.58, 0.03), improvement in quality of life (standardised mean difference -0.63, 95% CI -1.95, 0.70), or reduced neuropsychiatric symptoms (mean difference -1.06, 95% CI -2.16, 0.05). Narrative meta-synthesis revealed barriers (for example, time constraints) and enablers (for example, staff collaboration) to providing person-centred care from a staff perspective. Discussion and Implications The effectiveness of person-centred care initiatives delivered to people with dementia in residential aged care is conflicting. Further high-quality research over an extended time is required to identify how person-centred care can be best implemented to improve resident outcomes.