This systematic review and meta-analysis reported that proton therapy produced a better OS rate for extrahepatic biliary cancer, compared to photon radiotherapy. Based on data from 9 photon studies (2038 patients) and 2 proton studies (70 patients), the 1-year OS were 56% for the photon and 72% for the PT groups (p < 0.001). The median survival time was 13.1 months for the photon group and 18.8 months for the PT group (p = 0.03). The incidence rates of grade 3 ≤ toxicity was 18.5%-33% in the photon radiotherapy group and 2.9-15% in the PT group.