Six years after the Affordable Care Act (ACA) became law, the number of nonelderly Americans with health insurance has expanded by twenty million, and the uninsurance rate has declined nearly 9 percentage points. Nevertheless, public opinion about the law remains deeply divided. We investigated how individuals may be experiencing and responding to health reform implementation by analyzing three waves of a panel study we conducted in 2010, 2012, and 2014. While public opinion about the ACA remains split (45.6 percent unfavorable and 36.2 percent favorable), there have been several detectable shifts. The share of respondents believing that reform had little or no impact on access to health insurance or medical care diminished by 18 percentage points from 2010 to 2014, while those considering reform to have some or a great impact increased by 19 percentage points. Among individuals who held unfavorable views toward the law in 2010, the percentage who supported repeal—while still high, at 72 percent—shrank by 9 percentage points from 2010 to 2014. We found that party affiliation and distrust in government were influential factors in explaining the continuing divide over the law. The ACA has delivered discernible benefits, and some Americans are increasingly recognizing that it is improving access to health insurance and medical care.