Several provisions of the Affordable Care Act had the potential to reduce uninsurance rates for children. In this brief, we explored changes in coverage among children using data from the National Health Interview Survey. We found coverage gains among children in Medicaid expansion and nonexpansion states between 2013 and 2015, but we also observed an uptick in uninsurance from 2015 to 2017 among children in nonexpansion states. Health insurance gains among Hispanic children in Medicaid expansion states virtually eliminated the coverage gap between white and Hispanic children in those states by 2017, but in nonexpansion states, Hispanic children were more than twice as likely as white children to be uninsured. In 2017, uninsured children were also more likely than insured children to be teens and to live in the South.