Objective:Numerous e-health programs have shown the potential to enhance psychological and social health outcomes in informal caregivers of People with Dementia (PwD). However, there is still a need for evidence-based interventions tailored to the specific needs of this population, such as maintaining self-management and participating in meaningful activities. This mixed-methods study aims to evaluate the feasibility, acceptability, and preliminary effectiveness of a blended intervention based on acceptance and commitment therapy for informal caregivers of PwD, leading to a better understanding of intervention refinements for future controlled trials.Method:A single-arm clinical trial design is conducted. A total of 20 informal caregivers of PwD are recruited through memory clinics and social media platforms in the Netherlands. The ACT-IC intervention is delivered over a 9-week period and consists of a collaborative goal-setting session, nine online modules, and nine telephone-based motivational coaching sessions. Feasibility and acceptability are assessed using the attrition rate, adherence to, and engagement with the intervention, the proportion of missing data, and semi-structured interviews. Clinical outcome measures assess depression, anxiety, stress, sense of competence, burden, and self-efficacy at baseline and post-intervention.Results:Data collection will be completed by May 2023, and analyses are ongoing. Of the 20 caregivers, 19 completed the baseline assessment, and 3 dropped out. Results of an ANOVA investigating the effect of ACT-IC on the outcome measures at post-intervention will be reported, as well as the results of post-hoc analyses that explored the effect on outcomes of goal attainment and meaningful activities, observed use of the website, and reported adherence to the recommended frequency of website use.Conclusion:The result will contribute to the need for further research on supportive e-health interventions for informal caregivers of PwD. The ACT-IC study is the first trial to apply an evidence-based blended approach to address and evaluate the specific shared needs of caregivers. The mixed-method approach may offer a better understanding of reasons for dropouts, as well as barriers and facilitators that informal caregivers experience over the course of the intervention. Furthermore, social interaction (telephone-based motivational coaching) might improve the feasibility and acceptability of the online ACT intervention.