The Patient Protection and Affordable Care Act (ACA), enacted in 2010, held great promise for expanding insurance coverage to millions of uninsured Americans. Starting in 2014, it expanded Medicaid eligibility to low-income adults with family income below 138 percent of the federal poverty level. It also offered premium subsidies to people with income up to four times the poverty level so they could purchase private insurance through federal or state health insurance exchanges. While most of those expected to gain insurance coverage for the first time are adults, children stand to gain as well, since children are more likely to have health care coverage when their parents do too (DeVoe et al. 2015). In 2014, about 3.9 million children were estimated to be eligible but not enrolled in Medicaid or the Children's Health Insurance Program (CHIP), representing roughly two-thirds of all uninsured children (Kaiser Family Foundation 2015). This brief looks at the KidsWell Campaign, a multilevel effort designed to ensure access to health insurance for all children. It summarizes evaluation findings on two research questions: (1) to what extent has state grantees' participation in KidsWell strengthened advocacy networks and capacities so far? and (2) which advocacy activities do grantees believe to be most effective in securing policy advances for children's health care coverage?