Background: Our aim is to investigate the association of treatment with survival in patients with diffuse intrinsic pontine glioma (DIPG) by examining 6 historical treatment paths. Methods: We retrospectively analyzed data from 409 patients with radiologically centrally reviewed DIPG, sourced from the German Society of Pediatric Oncology and Hematology HIT-HGG trial database and the SIOPE-DIPG/DMG Registry. Survival outcomes were estimated using the Kaplan-Meier method, and univariable and multivariable Cox proportional hazard models were estimated to study treatment effects. Results: The median overall survival (OS) from diagnosis was 11.2 months (95% confidence interval [CI], 10.5-11.9). Patients who by choice received no frontline treatment had an OS of 3.0 months (95% CI, 2.0-4.0), while those treated with radiation therapy (RT) alone had a median OS of 10.4 months (95% CI, 9.1-11.8). Those receiving RT combined with chemotherapy had the longest median OS of 11.7 months (95% CI, 10.8-12.6). The median post-progression survival (PPS) was 4.1 months (95% CI, 3.5-4.7). Patients who relapsed and did not receive treatment had a PPS of 2.2 months (95% CI, 1.8-2.6), while those treated with chemotherapy alone had a PPS of 4.4 months (95% CI, 3.7-5.0), and those who underwent reirradiation, with or without chemotherapy, had the longest survival after relapse of 6.6 months (95% CI, 5.3-8.0). Treatment differences remained significant in multivariable analysis adjusted for age and symptom duration in both diagnosis and relapse setting. Conclusions: This study shows increased survival outcomes associated with radiation and chemotherapy treatment or a combination thereof, at diagnosis and relapse, in a historical DIPG cohort.