SummaryBackgroundPositive self‐care behaviours are more likely in young people who engage with allergy support groups, but reasons for this association are not well understood.ObjectivesThis study explored how and why young people engage with allergy support groups to identify what activities and resources are beneficial.MethodsIn‐depth, semistructured interviews were conducted with young people aged 12‐21 years who reported engaging with allergy support groups (in person or online). Interviews were audiotaped, transcribed verbatim and analysed using thematic content analysis.ResultsThe 21 participants had a range of allergies; initially, most joined support groups on suggestion of their parent/carer although older participants sought groups independently. Feeling included and sharing experiences with people with similar problems/challenges were highly valued. Through membership, young people reported improved self‐esteem and confidence in both managing their allergies and lives generally. Information, such as allergy alerts and hard‐hitting video campaigns, were reported to positively influence adherence to self‐care behaviours such as carrying medication. Participants wanted greater availability of allergy support groups, and higher profiles in health care and educational settings, as well as through social media.Conclusions and Clinical RelevanceParticipants valued the psychological and practical support of networking with others with allergies, and described how membership improved their confidence. This study also provides insight into the ways support groups improve young people's adherence to medical advice and positive self‐care behaviours; participants responded well to hard‐hitting video campaigns which appeared to emphasize the severity and susceptibility of anaphylaxis. Participants identified the need for more active promotion of support groups amongst young people and their clinicians, as well as making them available in more localities.