ISSUE. Prior research shows that low-income residents of states that expanded Medicaid under the Affordable Care Act are less likely to experience financial barriers to health care access, but the impact on out-of-pocket spending has not yet been measured. GOAL. Assess how the Medicaid expansion affected out-of-pocket health care spending for low-income families compared to those in states that did not expand and consider whether effects differed in states that expanded under conventional Medicaid rules vs. waiver programs. METHODS. Analysis of the Consumer Expenditure Survey 2010–2015. KEY FINDINGS AND CONCLUSIONS. Compared to families in nonexpansion states, low-income families in states that did expand Medicaid saved an average of $382 in annual spending on health care. In these states, low-income families were less like to report any out-of-pocket spending on insurance premiums or medical care than were similar families in nonexpansion states. For families that did have some out-of-pocket spending, spending levels were lower in states that expanded Medicaid. Low-income families in Medicaid expansion states were also much less likely to have catastrophically high spending levels. The form of coverage expansion — conventional Medicaid or waiver rules — did not have a statistically significant effect on these outcomes.