Background: Pediatric brain tumor survivors can experience detrimental effects from radiation treatment. This cross-sectional study examined psychosocial and executive functioning in pediatric patients treated with proton radiation (PRT). Procedure: Parents of 187 brain tumor survivors completed standardized scales ≥1 year after PRT. One-way analysis of variance, Pearson correlation, and chi-square analysis were used to determine the impact of demographic, diagnostic or treatment-related characteristics. One-sample t-tests compared mean scores with published normative means. Rates of impairment (T-score >65) were calculated. Results: Mean age at PRT (baseline) was 8.49 years; mean follow-up interval 3.84 years. Approximately one-third (36.9%) received craniospinal irradiation (CSI). All mean T-scores for psychosocial and executive functioning were within the normal range. Younger age at baseline correlated with more behavior problems; older age with more problems with adaptive skills. Baseline age was not correlated with executive functioning. Follow-up interval and radiation field (CSI; focal) were not related to psychosocial or executive problems. Significantly elevated mean T-scores were in withdrawal ( p<0.001) and metacognitive skills (e.g., working memory p<0.001); significantly lower ( p<0.05) in hyperactivity, aggression, conduct problems, adaptability, social skills, and behavioral regulation. Rates of impairment far exceeded expectation in overall metacognitive skills (18.7%), withdrawal (17.9%), and activities of daily living (15.0%). Impairment rates were not related to age at PRT or radiation field. Conclusions: Psychosocial and executive functioning was within the normal range, on average, at follow-up. However, elevated impairment rates were observed in specific aspects of functioning (e.g., withdrawal, metacognitive executive functioning). Targeted screening and proactive intervention are needed.