Background/aim: This study presents the joint experience of three centers in the treatment of patients with biliary tract tumors with radiation therapy (RT). Materials and methods: The records of 27 patients were retrospectively reviewed. All of the patients who had undergone surgical resection received postoperative adjuvant RT, whereas all of the patients who had not undergone a surgical resection received RT with palliative intent. Twenty patients with adequate performance status were treated with RT and chemotherapy, while the remaining seven patients were treated with RT alone. Results: Follow-up ranged from 1 to 44 months. Local control was not achieved in 10 out of 11 patients who had received RT with palliative intent. Systemic failure was observed in eight patients at 5 to 16 months. Fifteen patients died due to disease-related causes at 1 to 22 months. At 2 years, overall survival was 33% and disease-free survival was 19%. A surgical resection with curative intent predicted improved local failure-free survival and improved disease-free survival. Conclusion: Since local recurrence is still the leading cause of failure following postoperative RT and the outcome following palliative RT is far from satisfactory, the indications, the target volume, and the doses for RT should be reconsidered.