Hair loss was compared between surgery followed by craniospinal radiotherapy (CSRT) or chemotherapy then CSRT (C-CSRT) for medulloblastoma. The proportion of patients exhibiting hair loss in the cranial field was 70.0% (C-CSRT) versus 30.0% (CSRT) (95% CI: 14.7% to 58.9%; P = 0.002). The C-CSRT group also experienced more virtual/complete hair loss over the posterior fossa boost. Age was a significant contributor to hair loss in the cranial field. Persistent significant hair loss is an under-reported late effect of treatment that could influence quality of survival and should be considered in future trial design.