We investigated language development, relational aggression, and relational victimization in ethnically, socioeconomically diverse preschoolers. Relational aggression was positively related to language development. Girls were more relationally aggressive than boys, and higher-socioeconomic status (SES) children were more relationally aggressive and victimized than lower-SES children. Neither gender nor SES conclusively moderated the relation between language and relational aggression, though some findings suggest the possibility of stronger relations among boys and lower-SES children. Teachers agreed on ratings of relational aggression and relational victimization to a moderate extent.