If gender differences in posttraumatic stress disorder follow from culturally-defined roles and rules, they should be greater in societies that foster traditional views of masculinity and femininity than in societies that adhere to these traditions less rigidly. Data were collected 6 months after Hurricanes Paulina (Acapulco; N = 200) and Andrew (Miami; White n = 135; Black n = 135). In regression analyses predicting scores on the Revised Civilian Mississippi Scale, Sex × Cultural Group interactions emerged for the total scale and for subscales of Intrusion, Avoidance, and Remorse. Only a sex main effect (women higher) emerged for Arousal. Overall, the results indicated that Mexican culture amplified, whereas African American culture attenuated, differences in the posttraumatic stress of male and female disaster victims.