Public disability programs provide financial support to 12 million working-age individuals per year, though not all eligible individuals take up these programs. Mixed evidence exists regarding the impact of Medicaid eligibility expansion on program take-up, and even less is known about the relationship between Medicaid expansion and racial and ethnic disparities in take-up. Using 2009-2020 Current Population Survey (CPS) data, we compare changes in Supplemental Security Income (SSI) and Social Security Disability Insurance (SSDI) take-up among people with disabilities living in Medicaid expansion states, compared to people with disabilities living in non-expansion states, before and after Medicaid expansion. We further explore heterogeneity by race/ethnicity. We find that Medicaid expansion reduced SSI take-up among White and Hispanic respondents by 10% and 21%, respectively, and increased SSDI take-up among White and Black respondents by 9% and 11%, respectively. We further find that Medicaid expansion reduced the probability that disabled respondents had employer-sponsored health insurance by approximately 8%, an effect primarily observed among Black and other-race respondents, suggesting that expansion reduced job-lock among the SSDI-eligible, contributing to the observed increase in SSDI take-up.