Purpose: To investigate safety, response, and survival after ablative glass microsphere 90Y radioembolization for unresectable intrahepatic cholangiocarcinoma. Materials and Methods: A retrospective review of 37 radioembolizations in 28 patients treated with single compartment dose of ≥190 Gy encompassing >75% of the largest tumor was performed. Tumors were assessed for stage, morphology, and arterial supply. Response per Modified Response Evaluation Criteria in Solid Tumors (mRECIST), freedom from progression (FFP), progression-free survival (PFS), overall survival (OS), biochemical hepatic function, performance status, and adverse events were investigated. Results: The median highest dose per patient was 256.8 Gy (195.7–807.8). Objective response at 3 months was 94.1% (complete 44.1% and partial 50%). Median OS was not reached and the 30-month OS rate was 59%, with a median follow-up of 13.4 months (5.4–39.4). FFP in the radiated field and overall FFP at 30 months were 67% and 40%, respectively. Favorable arterial supply was associated with improved OS ( p = 0.018). Unfavorable arterial supply was associated with worse OS [HR 5.7 (95% CI 1.1–28.9, p = 0.034)], and PFS [HR 5.9 (95% CI 1.9–18.4, p = 0.002)]. Patients with mass-forming tumors had a survival benefit ( p = 0.002). Laboratory values and performance status did not significantly change 3 months after radioembolization. Grade 3 and 4 adverse events occurred in 2 (7.1%) patients. Conclusions: Radioembolization of unresectable intrahepatic cholangiocarcinoma with ablative intent has a high response rate, promising survival, and is well tolerated.