Individuals who engage in risky sexual behavior face the possibility of experiencing negative consequences. One tenet of social learning theory is that individuals engage in behaviors partly based on observations or perceptions of others engagement in those behaviors. The present study aimed to document these norms-behavior relationships for both risky and protective sexual behaviors, including alcohol-related sexual behavior. Gender was also examined as a possible moderator of the norms-behavior relationship. Undergraduate students (n = 759; 58.0% female) completed a Web-based survey, including various measures of drinking and sexual behavior. Results indicated that students underestimate sexual health-protective behaviors (e.g., condom use and birth control use) and overestimate the risky behaviors (e.g., frequency of drinking prior to sex, typical number of drinks prior to sex, and frequency of casual sex) of their same-sex peers. All norms were positively associated with behavior, with the exception of condom use. Furthermore, no gender differences were found when examining the relationship between normative perceptions and behavior. The present study adds to the existing literature on normative misperceptions as it indicates that college students overestimate risky sexual behavior while underestimating sexual health-protective behaviors. Implications for interventions using the social norm approach and future directions are discussed.