Background: Incurable cancer does not only affect patients, it also affects the lives of their partners. Many partners take on caregiving responsibilities. The burden of these caregiving tasks are often associated with physical, psychological, and social difficulties and many partners have unmet supportive care needs. Oncokompas is an eHealth self-management application to support partners in finding and obtaining optimal supportive care, tailored to their quality of life and personal preferences. A randomized controlled trial will be carried out to determine the efficacy and cost-utility of Oncokompas. Methods: A total of 136 adult partners of patients with incurable cancer will be included. Partners will be randomly assigned to the intervention group, which directly gets access to Oncokompas, or the waiting-list control group, which gets access to Oncokompas after three months. The primary outcome measure is caregiver burden. Secondary outcome measures comprise self-efficacy, health-related quality of life, and costs. Measures will be assessed at baseline, two weeks after randomization, and three months after the baseline measurement. Discussion: This study will result in evidence on the efficacy and cost-utility of Oncokompas among partners of patients with incurable cancer, which might lead to implementation of Oncokompas as a health service for partners of patients with incurable cancer.