The age-standardized incidence of central nervous system (CNS) tumors in children increased significantly by 0.93% per year between 2000 and 2020, representing an average increase of approximately 5 cases of brain tumors per year.; This increase is partly explained by improved detection of optic tract gliomas in at-risk children and by increased reporting of pituitary adenomas.; Fluctuations in the incidence of gliomas, gangliogliomas, and glioblastomas are, at least in part, the result of changes in classification over time; it is not possible to confirm or refute a change in the risk of developing high-grade gliomas (entities that now include tumors formerly classified as glioblastomas).; With regard to other types of tumors, with the exception of the very rare atypical teratoid/rhaboid tumors, the observed increases are, for the most part, due to advances in diagnosis or changes in classification.