Objective: Women assertively resisting sexual aggression have the best chances of avoiding completed rape. Especially with acquaintances, there are significant social and psychological barriers to resistance. Novel vignettes depicting acquaintance rape were designed to enhance self-efficacy, reduce unrealistic optimism, and empower assertive resistance. Participants: The data were collected using a Web-based survey of 449 female college students from multiple universities in August-October 2014. Methods: Between-subjects mixed-methods design. Participants were randomly assigned to read one of four vignettes and complete self-report measures of personal vulnerability, self-efficacy, and beliefs and intention about resistance. Results: Although vignettes did not impact self-efficacy, one vignette enhanced perceived controllability and decreased unrealistic optimism. Women who read about completed acquaintance rape described intention to use physically assertive responses at double the rate of women reading about successful resistance. Conclusions: As low-cost, easily disseminated materials, vignettes about sexual assault may enhance campus prevention efforts.