As part of the transition to a circular economy, the EU has been introducing a diverse range of initiatives along the entire life cycle of products. One such initiative aims to increase municipal recycling rates by improving household and packaging waste collection, sorting and recycling by consumers through the use of EU harmonised waste-sorting labels. To inform the evidence-based design and empirical testing of such labels, this report reviews the behavioural science literature for insights into the design of waste-sorting labels. The report derives key lessons, insights and implications from the literature reviewed and suggests concrete recommendations for the design of an effective and valued harmonised labelling system. Through careful interpretation of the limited evidence, the report provides insights regarding various crucial characteristics of waste-sorting labels, namely their presentation (in terms of clarity benefitting from consistent placement, conciseness, persuasiveness, compatibility with other labels, inclusion of instructions for the preparation of packaging components, minimum size, actionability/intuitiveness and consistent use of text and graphical elements), accessibility (the use of colours and of complementary digital solutions, actionability/intuitiveness, consistent use of text an graphical elements, minimum size, and clarity of presented information), and quality and content (in terms of perceived quality benefitting from accuracy, factuality, resistance to destruction, and consistent use of text and graphical elements). Taken together, these lessons, insights and recommendations can feed into a participatory and empirical approach to designing EU harmonised waste-sorting labels.