Abstract Children spend a significant amount of their time daily on digital devices using online services. While this can bring many advantages and benefits, it also entails dangers if not the online environment is not effectively regulated. Exposure to marketing of harmful products and services, particularly towards children, remains a pervasive challenge, despite the extensive evidence base documenting its negative impacts. This session will give an overview of integrating behavioural sciences with public health which suggested promising avenues for addressing the complexities of harmful digital marketing to children. Additionally, current tools developed by WHO Regional Office for Europe and Joint Actions, which Member States can use to address novel challenges like brand marketing will be presented. The tools help to map, monitor and regulate the digital marketing exposure of unhealthy foods and brands to children in their country. One focus will be on the need to objective monitoring of marketing exposure to inform policies and ensure that they are fit for purpose. This is particularly challenging, as traditional monitoring tools struggle to keep up with automated, targeted and personalized advertisements. Due to the complexity to successfully restrict marketing exposure to children, strong collaborations are needed. Collaborative efforts of the Joint Action PreventNCD and the WHO Europe will be presented. Specific goals set by the Joint Action, as well as the importance of a sustainable approach will be highlighted. A discussion on the way forward will focus on how tangible impact can be created in the WHO European Region. Key messages • Need for effective tools to address novel challenges and successfully monitor and regulate harmful marketing to children. • Need for integration of behavioural science and strong collaborations to create real impact.