Magnetic resonance-guided focused ultrasound (MRgFUS) capsulotomy is a promising treatment for refractory obsessive-compulsive disorder (OCD); however, long-term clinical outcome studies are lacking. We aimed to investigate the long-term efficacy and safety of MRgFUS capsulotomy in patients with refractory OCD. Ten of the eleven patients who underwent MRgFUS capsulotomy for treatment-resistant OCD between 2013 and 2014 were included in this study. Clinical outcomes were assessed after 10 years of follow-up post-MRgFUS capsulotomy using tools such as neuropsychological test, the Frontal Systems Behavior Scale (FrSBe), and a locally developed MRgFUS-patient-centered outcomes questionnaire. After 10 years of follow-up, there was a mean improvement of 52.3% in the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score. Seven out of the ten participants responded fully (Y-BOCS reduction ≥35% + CGI-I 1 or 2) to the procedure, two of whom achieved remission (Y-BOCS score ≤12 and CGI-S 1 or 2). Obsessive-compulsive symptoms and overall functioning significantly reduced and improved, respectively (Y-BOCS = 20.7 after 2 years vs. 16.4 after 10 years, p = 0.012; Global Assessment of Functioning = 57.4 after 2 years vs. 69.0 after 10 years, p = 0.011). The patients experienced significantly improved frontal lobe-related functions (FrSBe Sum before 91.0 ± 17.6 vs. after 78.6 ± 17.7, p < 0.05). No adverse effects, including cases of suicide and neurological deficits, were reported. The majority of the respondents were generally satisfied with MRgFUS capsulotomy. MRgFUS capsulotomy is an effective and safe treatment option for the treatment of severe refractory OCD with sustained efficacy even after 10 years.