This systematic review included 24 studies for analysis in order to compare the incidence of SMNs after proton and photon-based radiation for pediatric CNS tumors. A total of 418 SMNs were seen in 38,163 patients. The median follow-up was 8.8 years. The pooled incidence of SMNs was 1.8% with photons and 1.5% with protons. The most common SMN were gliomas (40.6%) followed by meningiomas (38.7%), sarcomas (4.8%), and thyroid cancers (4.2%). The median latency to SMN for photons and protons were 11.9 years and 5.9 years, respectively.