The relationship between parenting and physical aggression is well established. However, less consideration has been given to parenting and relational aggression. The present study investigated four aspects of maternal parenting--overreactivity, laxness, positive affect and negative affect--and their relationships to relational aggression, in a sample of ethnically and socioeconomically diverse families. In the overall sample, positive maternal affect predicted less relational aggression, and negative maternal affect predicted more relational aggression. Laxness was associated with relational aggression in girls. For European American participants, negative affect, overreactivity, and laxness predicted relational aggression, whereas these relationships did not hold for Puerto Rican families. When parenting predictors were considered together, negative affect emerged as the most consistent predictor of relational aggression. Results suggest the need for more research on predictors of relational aggression, and for continued consideration of gender and ethnicity.