Young people with Attention Deficit Hyperactivity Disorder (ADHD) can benefit from psychoeducation interventions. Co-design of these interventions increases engagement and impact. However, there are very few age-appropriate codesigned psychoeducational resources for young people with ADHD. Therefore an activity book prototype ('ADHD Hero Activity Book') was co-designed to teach 7-11-yearolds with ADHD about their condition and how to manage it more effectively. This paper describes the initial evaluation of this prototype. Nine parents and eleven children took part across nine online workshops and one phone call. The suitability and acceptability of the activity book prototype was explored, and areas of improvement identified. Sketch notes were taken for respondent validity and engagement purposes. Thematic analysis identified six themes: (1) Visual information; (2) Topic interest and engagement; (3) Importance of relatable content; (4) Importance of activity book interaction and age-appropriate content; (5) Positive aspects of ADHD and (6) The activity book as a communication aid. Improvement suggestions were also provided. Results indicate the activity book is suitable, acceptable and can act as a communication aid between young people and families. Future research may consider the development of versions of the activity book for adolescents with ADHD and young people with Autism Spectrum Disorder.