Grounded in associative learning theory and the match-up hypothesis, this study sought to determine how female athlete endorsers’ gender expression impacted perceptions of their effectiveness and endorser-product fit. A 2 (feminine/masculine characteristics) x 2 (feminine/masculine product) experimental design was conducted with 205 participants from two universities in the Northeast region of the United States. Hypotheses were tested using MANCOVA and ANCOVA and results indicated gender expression significantly impacted measures of endorser attractiveness, explaining 23% of the variance. However, gender expression had no impact on measures of expertise or trustworthiness. Further, gender expression was not significant on measures of endorser-product fit. The findings are consistent with associative learning theory and the match-up hypothesis and suggest that female athlete endorsers can be effective when endorsing sport products regardless of their gender expression.