This paper investigates how the expansion of social insurance affects households’ accumulation of debt. Insurance can reduce reliance on debt by lessening the financial impact of adverse events like illness and job loss. But it can also weaken the motive to self-insure through savings, and households’ improved financial resilience can increase access to credit. Using two quasi experimental research designs, we estimate the causal effect of expanded insurance on household debt, exploiting the staggered expansions of one of the largest US social insurance programs: Medicaid. We find that expanding Medicaid increased credit card borrowing by 2.2%. Decomposing this effect in a model of household borrowing, we show that increased credit supply in response to households’ improved financial resilience fully accounts for this rise in borrowing and contributed to 17% of the total welfare gains of expanding Medicaid.