To examine the association between psychologist and nurse practitioner scope-of-practice (SoP) regulations and pediatric mental health service access. A nationally representative sample of children with mental health needs was identified using 5 years of National Survey of Children's Health (2016-2020). Utilization was measured in two ways: (1) unmet mental health care needs and (2) receipt of mental health medication. Expanded SoP for psychologists and nurse practitioners was measured based on the child's state of residence and the year of the survey. The associations between both SoP expansion and both outcomes were assessed using logistic regression models adjusted for multiple covariates. The probability of having unmet mental health needs was 5.4 percentage points lower (95% CI - 0.102, - 0.006) for children living in a state with psychologist SoP expansion; however, there was no significant difference in unmet mental health needs between states with and without NP SoP expansion. The probability of receiving a mental health medication was 2.0 percentage points higher (95% CI 0.007, 0.034) for children living in a state with psychologist SoP expansion. Conversely, the probability of receiving a mental health medication was 1.5 percentage points lower (95% CI - 0.023, - 0.007) for children living in a state with NP SoP expansion. Expanded SoP for psychologists is associated with improved access to pediatric mental health care in terms of both unmet need and receiving medication. Expanded SoP for NPs, however, was not associated with unmet need and lower receipt of medication.