IntroductionThe challenges of global ageing and the growing burden of chronic diseases require innovative interventions acting on health determinants like social participation. Many older adults do not have equitable opportunities to achieve full social participation, and interventions might underempower their personal and environmental resources and only reach a minority. To optimise current practices, the Accompagnement-citoyen Personnalisé d’Intégration Communautaire (APIC), an intervention demonstrated as being feasible and having positive impacts, needs further evaluation.Methods and analysisA pragmatic multicentre, prospective, two-armed, randomised controlled trial will evaluate: (1) the short-term and long-term effects of the APIC on older adults’ health, social participation, life satisfaction and healthcare services utilisation and (2) its cost-effectiveness. A total of 376 participants restricted in at least one instrumental activity of daily living and living in three large cities in the province of Quebec, Canada, will be randomly assigned to the experimental or control group using a centralised computer-generated random number sequence procedure. The experimental group will receive weekly 3-hour personalised stimulation sessions given by a trained volunteer over the first 12 months. Sessions will encourage empowerment, gradual mobilisation of personal and environmental resources and community integration. The control group will receive the publicly funded universal healthcare services available to all Quebecers. Over 2 years (baseline and 12, 18 and 24 months later), self-administered questionnaires will assess physical and mental health (primary outcome; version 2 of the 36-item Short-Form Health Survey, converted to SF-6D utility scores for quality-adjusted life years), social participation (Social Participation Scale) and life satisfaction (Life Satisfaction Index-Z). Healthcare services utilisation will be recorded and costs of each intervention calculated.Ethics and disseminationThe Research Ethics Committee of the CIUSSS Estrie – CHUS has approved the study (MP-31-2018-2424). An informed consent form will be read and signed by all study participants. Findings will be published and presented at conferences.Trial registration number NCT03161860; Pre-results.