Objective: Nigeria’s effort to curb the spiralling pandemic of HIV has yielded little result despite her reputation as\ud the country with the second largest number of HIV infected persons in the world. Theories of preventive health\ud behaviour posit that perceived vulnerability to health threats motivates self-protective behaviour. This study aimed to\ud examine the predicting role of the psychosocial and gender factors in the perception of vulnerability to HIV infection.\ud Design: This survey study adopted a cross-sectional research design.\ud Method: Participants were young and middle aged adult-volunteers (N= 302, male = 181, female = 121, mean\ud age = 23.9 years) drawn from four local Governments in Benin City of Nigeria. Participants responded to a\ud standardized self-reported questionnaire consisting demographics, ambivalent sexism, gender stereotype, sexual\ud assertiveness, health locus of control, and perceived vulnerability scales. Data analyses include descriptive,\ud Pearson moment correlation, t-test, ANOVA and multiple regression analyses.\ud Result: Data showed that age, gender stereotype, hostile sexism, benevolent sexism, sexual assertiveness and\ud health locus of control jointly accounted for 24.4% (p < 0.001) of the variance observed in the participants’\ud perception of their vulnerability to HIV infection. Independently, only gender stereotype and hostile sexism\ud contributed significantly to the observed variance. Poor perception of vulnerability to HIV infection was significantly\ud and positively related to hostile sexism, benevolent sexism, gender stereotype and higher external locus of control.\ud Recommendation: Attitude change programmes should be more gender sensitive and targeted to challenge\ud sexist orientation, gender stereotypes and health belief system