Background and aims: Evidence suggests that autistic children and young people (CAYP) can benefit from age-appropriate psychoeducation. Co-design is a methodology that iteratively involves end users and stakeholders in producing an intervention which may increase engagement and impact. Few age-appropriate co-designed psychoeducation resources for autistic CAYP exist. Therefore, a paper-based resource was co-designed for autistic CAYP who attend mainstream primary education. The resource aims to educate CAYP about their autism and provide strategies to support them to live well with their autism. Methods: This paper describes the evaluation of the prototype resource through online workshops with 12 families and input from four specialist clinicians. The suitability and acceptability of the resource was explored, and sketch notes were taken for respondent validity and engagement purposes. Results: A reflexive thematic analysis identified six themes and two subthemes: (1) content appropriateness (subtheme: strategies and unpredictability); (2) relating to content, (3) feelings and emotions, (4) terminology (subtheme: literal thinking); (5) positivity, and (6) communication aid. Suggested improvements were also identified. Results suggest the resource is suitable and acceptable. Conclusions: Future intervention development research may consider individual differences of autistic CAYP and the co-design of resources for other age groups of neurodiverse populations.