The purpose of this study was to investigate the distinct forms (i.e., physical and relational) and functions (i.e., proactive and reactive) of aggressive behavior during early childhood (n = 101; M age = 45.09 months). Forms, but not functions, of aggressive behavior were stable over time. A number of contributors to aggression were associated with distinct subtypes of aggressive behavior. Females and socially dominant children were more relationally aggressive and older children were less physically aggressive than their peers. Longitudinal analyses indicated that social dominance predicted decreases in physical aggression and peer exclusion predicted increases in relational aggression. Overall, the results provide support for the distinction between subtypes of aggression in early childhood.