Purpose <p>Flourishing, or positive mental well-being, may be represented by social relationships, school motivation, and behavioral skills for engaging in meaningful activities. Parents of autistic adolescents demonstrate different response patterns to flourishing items on the National Survey of Children’s Health (NSCH) when compared to parents of non-autistic adolescents. To better understand the source of these differences, we examined the clarity and construct relevance of flourishing items for autistic adolescents (12–17 years).</p> Methods <p>Sixteen adolescents (Mean age = 14.6 years) and their parents participated in cognitive interviews, where they were prompted to discuss aloud how they interpreted each item and selected a response option. Parent responses were scored relative to their child’s response for direction (more or less favorable) and magnitude (distance between responses). A deductive thematic analysis was undertaken to identify sources of confusion and the perceived relevance of items to participants.</p> Results <p>Overall, 39% of dyad responses aligned, while 34% of parents’ responses were less favorable than their child’s self-rated score. Participants showed evidence of confusion around word choice for homework, arguing too much, and challenged normative language in homework and friendships questions. Participants recommended alternative response options that would better reflect their experiences of flourishing.</p> Conclusion <p>Autistic adolescents and their parents generally viewed the NSCH flourishing domains as relevant to adolescent well-being, while differing in how specific items were interpreted and applied. These findings highlight the importance of considering response interpretation when using flourishing indicators in population surveillance and subgroup comparisons involving autistic adolescents.</p>