The treatment of ischemic stroke due to large-vessel occlusion has been revolutionized by mechanical thrombectomy (MT), as multiple trials have consistently shown improved functional outcomes compared to standard medical management both in the early and late time windows after symptom onset. However, MT is an interventional procedure that is more costly than best supportive care (BSC). We set out to study the cost-utility and budget impact of MT + BSC versus BSC alone for large-vessel occlusion using a combined decision tree and Markov model. The analysis was conducted from a Belgian payer perspective over a lifetime horizon, and health states were defined by the modified Rankin Scale (mRS). The treatment effect of MT + BSC combined clinical outcomes from all published early and late treatment window studies showing improved mRS after 90 days. Resource use and utilities were informed by an observational Belgian study of 569 stroke patients. Long-term mRS transitions were sourced from the Oxford Vascular study. MT + BSC generated 1.31 additional quality-adjusted life years and resulted in cost savings of €10,216 per patient over lifetime. Deterministic sensitivity analyses demonstrated dominance of MT over a wide range of parameter inputs. In a Belgian setting, adding MT to BSC within an early time window for 1575 eligible stroke patients every year produced cost savings between €6.3 million (year 1) and €14.6 million (year 5), or a total cost saving of €56.2 million over 5 years. Mechanical thrombectomy is a highly cost-effective treatment for ischemic stroke patients, providing quality-adjusted survival at lower health care cost, both when given in an early time window, as well as in a late time window.