Little is known about the significance of cultural differences to how caregivers receive a diagnosis of neurodevelopmental disability. As part of a Fetal Alcohol Spectrum Disorder prevalence study among sentenced, detained youth, our qualitative study explored the experiences of diagnostic assessment among detained young people and their caregivers. We present findings from the perspectives of caregivers. In conversation with the sociology of diagnosis literature, we present vignettes of three Aboriginal and two non‐Aboriginal caregivers’ experiences of the diagnostic assessment process. We found that Aboriginal caregivers conceptualised their children’s diagnosis and ongoing management in the context of their family networks and community. In contrast, non‐Aboriginal caregivers focused on how the diagnosis would affect their child and interactions with various institutions including healthcare systems and schools. Caregivers’ engagement with diagnostic reports and resources also followed cultural lines. Reflections on intergenerational drinking were voiced by Aboriginal caregivers, who expressed shame at receiving diagnosis. These findings advance our appreciation of cultural difference in receiving a diagnosis, the examination of which is in its nascent stages. We also suggest ways to mitigate harm from a stigmatising diagnosis and soften the well‐established effects of medical dominance over the process of defining a person’s capacity and status.