AimTo evaluate the effectiveness, feasibility and acceptability of a multicomponent intervention for improving personal continuity for older patients in general practice.DesignA cluster randomised three-wedged, pragmatic trial during 18 months.Setting32 general practices in the Netherlands.Participants221 general practitioners (GPs), practice assistants and other practice staff were included. Practices were instructed to include a random sample of 1050 patients aged 65 or older at baseline and 12-month follow-up.InterventionThe intervention took place at practice level and included opTimise persOnal cOntinuity for oLder (TOOL)-kit: a toolbox containing 34 strategies to improve personal continuity.OutcomesData were collected at baseline and at six 3-monthly follow-up measurements. Primary outcome measure was experienced continuity of care at the patient level measured by the Nijmegen Continuity Questionnaire (NCQ) with subscales for personal continuity (GP knows me and GP shows commitment) and team/cross-boundary continuity at 12-month follow-up. Secondary outcomes were measured in GPs, practice assistants and other practice staff and included work stress and satisfaction and perceived level of personal continuity. In addition, a process evaluation was undertaken among GPs, practice assistants and other practice staff to assess the acceptability and feasibility of the intervention.ResultsNo significant effect of the intervention was observed on NCQ subscales GP knows me (adjusted mean difference: 0.05 (95% CI −0.05 to 0.15), p=0.383), GP shows commitment (0.03 (95% CI −0.08 to 0.14), p=0.668) and team/cross-boundary (0.01 (95% CI −0.06 to 0.08), p=0.911). All secondary outcomes did not change significantly during follow-up. Process evaluation among GPs, practice assistants and other practice staff showed adequate acceptability of the intervention and partial implementation due to the COVID-19 pandemic and a high perceived workload.ConclusionAlthough participants viewed TOOL-kit as a practical and accessible toolbox, it did not improve personal continuity as measured with the NCQ. The absence of an effect may be explained by the incomplete implementation of TOOL-kit into practice and the choice of general outcome measures instead of outcomes more specific for the intervention.Trial registration numberInternational Clinical Trials registry Platform (ICTRP), trial NL8132 (URL: ICTRP Search Portal (who.int).