Advanced hybrid closed-loop (AHCL) automated insulin delivery systems are the most effective therapy in terms of assisting people with type 1 diabetes (T1D) to achieve glycemic targets; however, the cost can represent a barrier to uptake. In this study, a cost-utility analysis of the MiniMed™ 780G AHCL system (MM780G) versus intermittently scanned continuous glucose monitoring (is-CGM) plus multiple daily insulin injections (MDI) in people with T1D not achieving glycemic goals was performed across six European countries. Clinical input data were sourced from the ADAPT trial. Assuming a baseline HbA1c of 9.04%, HbA1c reductions of 1.54% for AHCL and 0.2% for is-CGM+MDI were modeled. The analyses were performed from a payer perspective over a time horizon of 40 years and an annual discount rate of 3% was applied. Across all countries, the use of AHCL was projected to result in an incremental gain in quality-adjusted life expectancy of >2 quality-adjusted life years (QALYs) versus is-CGM+MDI. Lifetime direct costs were higher with AHCL resulting in incremental cost-utility ratios for AHCL versus is-CGM+MDI ranging from EUR 11,765 per QALY gained in Austria to EUR 43,963 per QALY gained in Italy. For people with T1D managed with is-CGM+MDI not achieving glycemic targets, initiation of the MM780G system was projected to improve long-term clinical outcomes; however, due to differences in health care costs between countries, the health economic outcomes differed. In all included countries, AHCL is likely to be cost-effective relative to is-CGM+MDI for people not achieving glycemic goals with is-CGM+MDI. The ADAPT trial is registered with ClinicalTrials.gov, NCT04235504.