OBJECTIVE: Certain antihyperglycemic therapies modify cardiovascular and kidney outcomes among patients with type 2 diabetes, but early uptake in practice appears restricted to particular demographics. We examine the association of Medicaid expansion with use of and expenditures related to antihyperglycemic therapies among Medicaid beneficiaries. RESEARCH DESIGN AND METHODS: We employed a difference-in-difference design to analyze the association of Medicaid expansion on prescription of noninsulin antihyperglycemic therapies. We used 2012-2017 national and state Medicaid data to compare prescription claims and costs between states that did (n = 25) and did not expand (n = 26) Medicaid by January 2014. RESULTS: Following Medicaid expansion in 2014, average noninsulin antihyperglycemic therapies per state/1,000 enrollees increased by 4.2%/quarter in expansion states and 1.6%/quarter in nonexpansion states. For sodium-glucose cotransporter 2 inhibitors (SGLT2i) and glucagon-like peptide 1 receptor agonists (GLP-1RA), quarterly growth rates per 1,000 enrollees were 125.3% and 20.7% for expansion states and 87.6% and 16.0% for nonexpansion states, respectively. Expansion states had faster utilization of SGLT2i and GLP-1RA than nonexpansion states. Difference-in-difference estimates for change in volume of prescriptions after Medicaid expansion between expansion versus nonexpansion states was 1.68 (95% CI 1.09-2.26; P < 0.001) for all noninsulin therapies, 0.125 (-0.003 to 0.25; P = 0.056) for SGLT2i, and 0.12 (0.055-0.18; P < 0.001) for GLP-1RA. CONCLUSIONS: Use of noninsulin antihyperglycemic therapies, including SGLT2i and GLP-1RA, increased among low-income adults in both Medicaid expansion and nonexpansion states, with a significantly greater increase in overall use and in GLP-1RA use in expansion states. Future evaluation of the population-level health impact of expanded access to these therapies is needed.