In the current paper, two short-term longitudinal studies were conducted to examine relational aggression and relational bullying as differential predictors of relational victimization and health-related outcomes (i.e., social maladjustment problems). In Study 1, teachers completed reports of preschoolers' (N = 124; [mean] age = 44.88 months; SD = 4.52; 41.1% girls) physical and relational aggression, bullying behavior, and peer victimization at two time points. Hierarchical models revealed that, consistent with study hypotheses, relational aggression but not relational bullying predicted increases in relational victimization. Study 2 (N = 105; [mean] age = 46.78 months; SD = 7.47; 52.4% girls) improved upon several limitations of Study 1 by having multiple informants and addressing collinearity concerns. Specifically, two variables were created, relational severity and relational directionality, reflecting the commonalities and differences between relational aggression and relational bullying respectively. Results of Study 2 generally replicated the overall pattern of findings of Study 1 with a more conservative model. Results indicated that relational directionality tended to be negatively associated with increases in social maladjustment problems. These results suggest that, relative to relational bullying, relational aggression tended to be associated with increases in social maladjustment problems. These findings provide support for distinguishing between subtypes of both aggression and bullying behavior (i.e., physical and relational) in the developmental literature. (author abstract)