ObjectivesTo understand and assess the degree of personalisation of tailored activities for people with dementia (PWD); and to estimate the magnitude of the effects of levels of personalisation on reducing behavioural and psychological symptoms of dementia (BPSD), improving quality of life (QoL) and level of engagement.DesignSystematic review with meta-analysis.Data sourcesProQuest, PubMed, Ovid, Cochrane Library, Web of Science and CINAHL were searched from the start of indexing to May 2020.Eligibility criteriaWe included randomised controlled trials and quasi-experimental studies assessing the effects of tailored activities for people aged 60 years or older with dementia or cognitive impairment on the outcomes of BPSD, QoL, depression and level of engagement with control groups.Data extraction and synthesisTwo researchers screened studies, extracted data and assessed risks of bias. A rating scheme to assess the degree of personalisation of tailored activities was developed to classify tailored activities into high/medium/low groups. Effect sizes were expressed using standardised mean differences at 95% Confidence Interval (CI). Subgroup analyses were conducted to assess whether the degree of personalisation of tailored activities affected outcomes of interest.ResultsThirty-five studies covering 2390 participants from 16 countries/regions were identified. Studies with a high-level of personalisation interventions (n=8) had a significant and moderate effect on reducing BPSD (standardised mean differences, SMD=−0.52, p<0.05), followed by medium (n=6; SMD=−0.38, p=0.071) and low-level personalisation interventions (n=6; SMD=−0.15, p=0.076). Tailored activities with a high-level of personalisation had a moderate effect size on improving QoL (n=5; SMD=0.52, p<0.05), followed by a medium level (n=3; SMD=0.41, p<0.05) of personalisation.ConclusionsTo develop high-level tailored activities to reduce BPSD and improve QoL among PWD, we recommend applying comprehensive assessments to identify and address two or more PWD characteristics in designed tailored activities and allow modification of interventions to respond to changing PWD needs/circumstances.PROSPERO registration numberCRD42020168556.