ABSTRACT. Collegiate females in the United States are susceptible to sexually transmitted infections (STIs) due to their propensity for sexual exploration, multiple sexual partnerships, and inconsistent safe-sex practices. Despite the potential for safe-sex communication to contribute to safer sex, little is known about the predictors of this form of sexual communication. Research on condom assertiveness—the unambiguous messaging that sex without a condom is unacceptable—is especially rare. This study employed the Expanded Health Belief Model (EHBM) in an attempt to understand why some collegiate females are more condom assertive than others. Compared with less condom-assertive females, more condom-assertive females have more faith in the effectiveness of condoms, believe more in their own condom communication skills, perceive that they are more susceptible to STIs, believe there are more relational benefits to being condom assertive, believe their peers are more condom assertive, and intend to be more condom assertive. Overall, EHBM variables accounted for nearly 70% of the variability in condom assertiveness. Several of these associations, however, were moderated by sexual compulsivity and general assertiveness. Implications of these findings for sexual health practitioners are discussed, and directions for future research are suggested.