Background: Globally, family members account for the main source of caregiving of persons with dementia living at home. Providing care to family members with dementia often has negative health consequences for caregivers such as stress, depression and low quality of life. Yet, formal support for family caregivers (FCs) is limited. Telehealth technology has the potential to provide health care and social support to FCs. This study aims to assess the effectiveness of providing support by healthcare professionals (HPs) through a mobile app in reducing stress, depressive symptoms and loneliness, and improving mental health and quality of life of FCs of persons with dementia. Methods: Using a pragmatic intervention design, this study will use pre- and post-intervention assessment to evaluate the effectiveness of the proposed intervention in a sample of 78 FCs of persons with dementia (PWD). The intervention will be implemented by approximately 5 HPs specialized in dementia care based in the municipalities in Sweden. The main thrust of the intervention is to provide professional support, with help of an interactive mobile app, to family members in their caregiving role for PWDs. Qualitative interviews with HPs and FCs form the groundwork of the development of the mobile app. By using the app on smart phone or tablet, the FC, in groups of 8-10, will communicate with peers and a HP exchanging ideas on how to deal with PWD's behavioral and cognitive changes and get support. They will also be able to discuss stressful events and access mindfulness exercises focused on themselves. Quantitative data will be collected before and at three time points after the 8-week intervention to assess changes in the health outcomes of the FCs. In-depth interviews will be conducted after the intervention to capture the experiences of FCs and HPs regarding the ease of use and acceptability of the app.Discussion: This tailor-made mobile app has the high potential to be a practical platform for supporting FCs to alleviate stress and improve mental health irrespective of distance to the nearest health care or social service center.Trial Registration: ISRCTN, ISRCTN46137262 . Registered 10 October 2019.