Objectives <p>Children and Youth with Special Healthcare Needs (CYSHCN) have high rates of unmet health care need, particularly mental health. To increase access to mental health care, policymakers support pediatric subspecialists providing mental health care. Yet it is unclear how great the need for this role might be. This study described mental health care needs among CYSHCN who needed pediatric subspeciality care, and rates at which needs go unmet.</p> Methods <p>We conducted a retrospective cohort study of 20,335 CYSHCN who needed subspecialist care from 2016 to 2021 using pooled National Survey of Children’s Health data. Analysis described rates of mental health care need and unmet need.</p> Results <p>40% (<i>N</i> = 8,538) of CYSHCN who needed subspecialist care had mental health care needs. CYSHCN receiving care from a specialist had a significantly lower unmet need for mental health care, compared to those who did not receive specialist care (12.5% vs. 43.5%). Receiving subspecialist care was associated with a 24-percentage point decrease in unmet mental health need.</p> Conclusions for Practice <p> CYSHCN who receive subspecialist care have high rates of mental health care need, most need is met. Future work should explore strategies to support subspecialists in the provision of holistic, physical, and mental, health care without assuming roles as mental health care providers.</p>