Background/Objectives: Chronic migraine is a disabling neurological disorder that significantly impairs quality of life. Interventional procedures, including greater occipital nerve (GON) block and sphenopalatine ganglion (SPG) block, are increasingly used as adjuncts to standard pharmacological treatment. The aim of this study was to compare the effectiveness of GON and SPG blocks in patients with chronic migraine. Methods: This retrospective observational study included 50 patients diagnosed with chronic migraine according to the International Classification of Headache Disorders, 3rd edition (ICHD-3). Patients were assigned to either a GON block group or an SPG block group. Monthly migraine days, pain intensity measured using the Visual Analog Scale (VAS), and migraine-related disability assessed with the Headache Impact Test-6 (HIT-6) and Migraine Disability Assessment (MIDAS) questionnaires were evaluated before treatment and after completion of two procedures. Results: Both GON and SPG blocks were associated with significant reductions in monthly migraine days, pain intensity, and disability scores. A greater reduction in monthly migraine days was observed in patients treated with GON block compared with those treated with SPG block. Conclusions: Both GON and SPG blocks may represent effective adjunctive treatment options for patients with chronic migraine. In this study, GON block was associated with a greater reduction in migraine frequency, although further prospective studies are needed to confirm these findings.