This study examines the effects of mental health parity laws on mental health care utilization and mental health outcomes of children and adolescents from middle-income households in the context of the 2008 Mental Health Parity and Addiction Equity Act (MHPAEA), using data from the 2007 and 2011–2012 waves of the National Survey of Children’s Health (N = 57,549). A difference-in-differences method controlling for demographic characteristics, state Medicaid eligibility, and unemployment is used. The analyses show that after the enactment of the MHPAEA, children and adolescents with family income between 150 and 400% of the federal poverty level in states without prior parity laws experience a 2.80 percentage point relative increase (p < 0.01) in mental health care utilization. These children and adolescents also experience an increase in the diagnoses of anxiety, which may suggest that better access to healthcare increases screening for previously under-diagnosed disorders.