Problem: Low mental health among children is an increasing problem in public health which increase the risk of developing mental and physical health problems. Supporting child mental health is crucial for the child’s quality of life, cognitive development, socioemotional function and for relational attachment. Previous research shows a great potential for addressing the problem with an early universal parent-oriented intervention during pregnancy and the first two years of the child’s life. The department of health in Denmark recommend a high-risk intervention combined with an early universal parent-oriented intervention. Research supports this theory by clarifying, that the incidence exists in the general population and not in the high-risk group. Thisted Kommune provides a high-risk intervention, but not an early universal parent-oriented intervention, why there is an untapped potential to address the problem.Aim: Thisted Kommune is preparing a new health strategy. The aim of this thesis is to contribute to their decision about offering an early universal parent-oriented intervention by providing a knowledge base.Method: The thesis is based on the core elements in the Medical Research Council (MRC) framework and a critical realistic perspective. Based on a systematic literature study, an initiating program theory is initially prepared, which is respectively tested and refined through a focus group interview with health care visitors and three individual interviews with parents. All informants had experience with an early universal parent-oriented intervention. The analysis is carried out retroductively based on a critical realist analysis strategy, as described by Gilmore et al. (2019).Results: The result of the thesis shows that there is both potentials and limitations associated with an early universal parent-oriented intervention aimed at promoting children’s mental health. Based on the results from the study, there is developed eight recommendations for addressing the problem, in Thisted Kommune, which include which format and which content is effective, as well as which unintended consequences must be considered.Conclusion: It is possible to promote children’s mental health through an early universal parent-oriented intervention with the right format and content, as a supplement to a high-risk intervention. The next step for Thisted Kommune is to bring this knowledge base into consideration and either develop or adapt an early universal parent-oriented intervention where the recommendations identified as effective are considered.