Abstract Purpose (1) To assess prevalence of physical dating aggression and victimization among high school students; (2) to assess prevalence of mutual and exclusive aggression; (3) to determine whether aggression differs across ethnic groups and relationship type; and (4) to ascertain the likelihood of injury and breakup in individuals who reported that they were the recipients of physical aggression. Methods Students (N = 2363) from seven multiethnic high schools participated. Because males in high school date females younger than they and the reverse for females, and because males and females may underreport aggression, only within gender comparisons were conducted. Results More females reported engaging in physical aggression (40%) than reported being victims of aggression (30%). Fewer males reported engaging in physical aggression (24%) than reported being victims of physical aggression (31%). If physical aggression occurred, typically both partners were aggressive. For females, exclusive engagement in physical aggression (perpetration) was reported at higher rates than exclusively being the recipient of physical aggression (victimization) and vice versa for males. Dating aggression was less prevalent among male Asian students than other ethnic groups. Engaged males and females reported the highest rates of physical aggression. Injury was reported by over 25% of males and females who reported being the recipients of physical aggression. Conclusions Dating aggression intervention programs should address physical aggression of both males and females. Because approximately 30% of the high school males and females reported being the recipients of physical aggression by their partners, primary prevention efforts should occur before high school.