•This co-produced study explores how young people experience and conceptualise ‘feeling (mis)understood’ by adults.•Feeling understood by adults has a positive impact on young people’s mental health and help-seeking.•When young people feel misunderstood by health and social care professionals, it can negatively impact help-seeking.•Health and social care professionals should help young people to feel understood in to support engagement. The subjective and emotional experience of feeling (mis)understood by another person is distinct from being literally (mis)understood. While there is literature exploring young people’s experiences of feeling (mis)understood in therapeutic or clinical settings by adults and the impacts thereof, there is limited exploration of young people’s conceptualisations and perspectives of feeling (mis)understood within a range of young person-supporting adult relationships. This paper reports on the first stage of a project that was co-designed and co-produced by young people, exploring how young people experience and conceptualise ‘feeling (mis)understood’ in the context of receiving support from adults in their lives. This initial stage of the project captures young people’s views on what feeling (mis)understood feels like, its impact on their mental health, and how adults can help young people to feel understood. Conceptualisation, design, fieldwork, analysis and writing were all co-produced with peer-researchers. Data for this project was generated through four workshops each held in England, Scotland, Wales and Northern Ireland. A total of 26 participants aged between 16 and 24 years of age took part in these workshops, and each workshop was facilitated by two peer-researchers and a member of university staff. Data was analysed through collaborative thematic analysis. The study found that feeling understood by supporting adults has a very positive impact on young people’s wellbeing, mental health and help-seeking behaviour. Feeling misunderstood was found to have the converse effect, and in addition was found to make young people less likely to seek further support. Young people also identified a number of key actions adults can take to help the young people they support feel better understood. The findings of this research suggest that practitioners in the health and social care sector working with young people should consider the ways in which they can help young people feel better understood.