<p>Sexual rape fantasies are commonly reported among women. Rape fantasies can range anywhere from violent, forceful encounters to seduction fantasies where the fantasizer is coerced by an attractive partner. Although rape fantasies often contain aversive content, research tends to broadly conceptualize sexual fantasy as a universally pleasurable experience. The current research explored the possible function of aversive rape fantasy in women, hypothesizing that such fantasies are part of the output of a threat management system for rape avoidance. The fantasy is argued to function as a form of mental rehearsal wherein more realistic and forceful rape fantasies provide the fantasizer a low-cost, high-reward method for simulating and preparing for a potential future attack. Results of an online survey study indicated that women’s fear of rape was positively associated with the presence of aversiveness in rape fantasies, but not other types of fantasies, when controlling for the eroticism of women’s rape fantasies and other types of fearfulness. Women’s history of sexual assault was also positively associated with the aversiveness of their rape fantasies—a relationship that was mediated by women’s fear of rape. These findings are consistent with the threat management system model and may imply that women who are more vulnerable to victimization are more fearful of rape and therefore engage in mental rehearsal of possible rape encounters through aversive rape fantasies as a means of defensive vigilance against potential future assaults.</p>