Abstract Background Rehabilitation pathways are crucial to reduce stroke-related disability. Motivational Interviewing (MI), as a person-centered complex intervention, aimed to empower and motivate, and could be a resource to improve rehabilitation outcomes for older stroke survivors. The IMAGINE project aims to assess the impact of MI, as a complement to standard geriatric rehabilitation, on functional improvement at 30 days after admission, compared to standard geriatric rehabilitation alone, in persons admitted to geriatric rehabilitation after a stroke. Secondary objectives include assessing the impact of MI on physical activity and performance, self-efficacy, safety, cost-utility, participants’ experiences and functional status at 3 months. Methods We will conduct a multicenter randomized clinical trial in three geriatric rehabilitation hospitals in Spain. Older adults after mild-moderate stroke without previous severe cognitive impairment or disability will be randomized into the control or intervention group (136 per group, total N = 272). The intervention group will receive 4 sessions of MI by trained nurses, including the design of a personalized rehabilitation plan agreed between stroke survivors and nurses based on stroke survivors´ goals, needs, preferences and capabilities. Main outcome will be the Functional Independence Measure (FIM). In-hospital physical activity will be measured through accelerometers and secondary outcomes using validated scales. The study includes a process evaluation and cost-utility analysis. Discussion Final results are expected by end of 2020. This study will provide relevant information on the implementation of MI as a rehabilitation reinforcement tool in older stroke survivors. A potential reduction in post-stroke disability and dependence would increase person’s health-related quality of life and well-being and reduce health and social care costs. IMAGINE has the potential to inform practice and policymakers on how to move forward towards shared decision-making and shared responsibilities in the vulnerable population of older stroke survivors. Trial registration ClinicalTrials.gov: NCT03434938, registered on January 2018.