We analyze whether the Affordable Care Act (ACA) has affected labor supply of older Americans using data that span more than four years after the policy’s implementation in 2014. We find no changes in labor supply of older Americans either in response to subsidized marketplace coverage, which became available nationally in 2014, or in response to the expansion of Medicaid eligibility in some states but not others. We analyze multiple dimensions of labor supply — labor force participation; employment; full-time work conditional on employment — as well as several measures of retirement including self-reported retirement and the receipt of retirement income. We fail to find labor supply effects even for subgroups with less than a high school education or those with fair or poor health, who might have been expected to have a greater labor supply response. The lack of a labor supply response stands in contrast to the large gains in coverage observed in 2014. These results suggest that for Americans approaching retirement the Affordable Care Act achieved its primary goal of increasing coverage without the unintended consequence of reducing labor supply.