Responses to conflict were studied in samples of college students from a highly collectivistic society (China, n = 207) and a highly individualistic society (United States n = 209). As predicted, the collectivistic society reported more conflict-reducing behaviors and less verbal or physical aggression. However, the effect of individualism/collectivism was moderated by both the ingroup/outgroup status of the target and gender of the participant. Chinese and US women did not differ on any measure. However, of the four groups, Chinese men reported the most conflict-reducing behaviors and the least physical aggression, whereas US men reported the fewest conflict-reducing behaviors and the greatest physical aggression. As predicted, conflict-reducing behaviors were more common in the ingroup condition and both verbal and physical aggression was more common in the outgroup condition. However, the latter were moderated by gender of the participant. US men reported greater physical aggression than any other group. Neither gender nor society had any effect on the level of indirect aggression. There were no gender or individualism/collectivism effects on indirect aggression. Observed gender effects were attributed to differences in how collectivistic and individualistic societies conceptualize masculinity. The effect sizes associated with the ingroup/outgroup condition were consistently and substantially larger than effect sizes associated with individualism/collectivism or gender. Aggr. Behav. 37:302–314, 2011. © 2011 Wiley-Liss, Inc.