The subgroups identified were a nonaggressive peer group, in which female friends had not been sexually victimized and male friends had not been sexually aggressive; a female victimization peer group, which included female friends who had been sexually victimized but no male friends who had been sexually aggressive; and a sexually aggressive peer group, which included both males who had been sexually aggressive and females who had been sexually victimized. The data used in the current study came from self-administered mail-out/mail-back questionnaires sent to random samples of undergraduates at a large public university on the West Coast in 1982 and 1987. The response rates were 56 percent in 1982 and 72 percent in 1987, with 224 and 485 students, respectively, returning questionnaires with complete data on the variables of interest. The survey inquired about the number of male friends who had been sexually aggressive and the number of female friends who had been victimized by sexually aggressive dates. Data from the current study confirm the presence of the three types of mixed-sex peer groups with distinctly varying involvements in sexual aggression. Suggestions for further research are offered. 3 tables, 6 notes, 31 references.