Abstract Background There is a lack of well-conducted randomized controlled trials evaluating the effectiveness of theory-based online interventions for eczema. To address these deficiencies, we previously developed and demonstrated the effectiveness of two online behavioural interventions: Eczema Care Online for parents/carers of children with eczema, and Eczema Care Online for young people with eczema. Objectives To explore the views and experiences of people who have used the Eczema Care Online interventions to provide insights into how the interventions worked and identify contextual factors that may impede users’ engagement with the interventions. Methods Qualitative semistructured interviews were conducted with 17 parents/carers of children with eczema and 17 young people with eczema. Participants were purposively sampled from two randomized controlled trials of the interventions and recruited from GP surgeries in England. Transcripts were analysed using inductive thematic analysis, and intervention modifications were identified using the person-based approach table of changes method. Results Both young people and parents/carers found the interventions easy to use, relatable and trustworthy, and perceived that they helped them to manage their eczema, thus suggesting that Eczema Care Online may be acceptable to its target groups. Our analysis suggested that the interventions may reduce eczema severity by facilitating empowerment among its users, specifically through improved understanding of, and confidence in, eczema management, reduced treatment concerns, and improved treatment adherence and management of irritants/triggers. Reading about the experiences of others with eczema helped people to feel ‘normal’ and less alone. Some (mainly young people) expressed firmly held negative beliefs about topical corticosteroids, views that were not influenced by the intervention. Minor improvements to the design and navigation of the Eczema Care Online interventions and content changes were identified and made, ready for wider implementation. Conclusions People with eczema and their families can benefit from reliable information, specifically information on the best and safest ways to use their eczema treatments early in their eczema journey. Together, our findings from this study and the corresponding trials suggest wider implementation of Eczema Care Online (EczemaCareOnline.org.uk) is justified.