Medical advances have improved the survival rate of children with brain tumors, allowing research on long-term outcomes. Prior research suggests that social functioning is often negatively affected by brain insults, and social functioning may be related to childhood receptive vocabulary in children with traumatic brain injuries (Greenham et al., 2010). The current study addressed this hypothesis with children diagnosed with pediatric brain tumors longitudinally using latent growth curve modeling (LGCM). Our sample consisted of 154 children with 544 evaluations from 2 to 7 years post diagnosis. All children completed the Peabody Picture Vocabulary Test Revised (PPVT-R) and Vineland Socialization Scale. Participants were diagnosed with mixed tumor types and diverse tumor locations. The average time since diagnosis was used to determine the latent growth curve factor loading (2, 2.5, 3, 4, 5, 6, 7 years post diagnosis). Results indicated that the predictors (PPVT-R and radiation therapy) accounted for 41% of the variance of the slope of socialization behavior and 38% of the variance of the intercept. Socialization and PPVT-R scores were significantly positively correlated (intercept γ=.47, p