OBJECTIVE The prevalence of type 2 diabetes is increasing among adults under age 45. Onset of type 2 diabetes at a younger age increases an individual’s risk for diabetes-related complications. Given the lasting benefits conferred by early glycemic control, we compared glycemic control and initial care between adults with younger onset (21–44 years) and mid-age onset (45–64 years) of type 2 diabetes. RESEARCH DESIGN AND METHODS Using data from a large, integrated health care system, we identified 32,137 adults (aged 21–64 years) with incident diabetes (first HbA1c ≥6.5% [≥48 mmol/mol]). We excluded anyone with evidence of prior type 2 diabetes, gestational diabetes mellitus, or type 1 diabetes. We used generalized linear mixed models, adjusting for demographic and clinical variables, to examine differences in glycemic control and care at 1 year. RESULTS Of identified individuals, 26.4% had younger-onset and 73.6% had mid-age–onset type 2 diabetes. Adults with younger onset had higher initial mean HbA1c values (8.9% [74 mmol/mol]) than adults with onset in mid-age (8.4% [68 mmol/mol]) (P < 0.0001) and lower odds of achieving an HbA1c CONCLUSIONS Adults with onset of type 2 diabetes at a younger age were less likely to achieve glycemic control at 1 year following diagnosis, suggesting the need for tailored care approaches to improve outcomes for this high-risk patient population.