Objectives. To document how health insurance coverage changed for White, Black, and Hispanic adults after the Affordable Care Act (ACA) went into effect. Methods. We used data from the American Community Survey from 2008 to 2014 to examine changes in the percentage of nonelderly adults who were uninsured, covered by Medicaid, or covered by private health insurance. In addition to presenting overall trends by race/ethnicity, we stratified the analysis by income group and state Medicaid expansion status. Results. In 2013, 40.5% of Hispanics and 25.8% of Blacks were uninsured, compared with 14.8% of Whites. We found a larger gap in private insurance, which was partially offset by higher rates of public coverage among Blacks and Hispanics. After the main ACA provisions went into effect in 2014, coverage disparities declined slightly as the percentage of adults who were uninsured decreased by 7.1 percentage points for Hispanics, 5.1 percentage points for Blacks, and 3 percentage points for Whites. Coverage gains were greater in states that expanded Medicaid programs. Conclusions. The ACA has reduced racial/ethnic disparities in coverage, although substantial disparities remain. Further increases in coverage will require Medicaid expansion by more states and improved program take-up in states that have already done so.