Background: The global sportswear industry relies heavily on celebrity athlete endorsements to influence consumer perceptions and drive sales. Major brands such as Nike, Adidas, and Under Armour have made athlete partnerships a central part of their marketing strategies. While male athletes have traditionally dominated the campaigns, the visibility and cultural impact of female athletes are now rapidly increasing. However, it remains unclear how the gender of the athlete endorser and the gender of the consumer together influence endorsement effectiveness in sportswear marketing.

Purpose: This thesis aims to explore how endorser gender and consumer gender influence key endorsement outcomes, namely Brand Attitude and Purchase Intention, and which constructs best explain these responses in sportswear marketing. To do this, the study draws on four theoretical frameworks: the Source Credibility Model extended with the Source Attractiveness Model, the Social Identity Theory, the Meaning Transfer Model, and the Match-Up Hypothesis, to understand how gender affects the endorsement process from athlete to consumer.

Method: The study adopted a sequential mixed-methods design. In the qualitative phase, 10 semi-structured interviews were conducted with sportswear consumers to identify relevant endorsement themes and constructs, which directly informed the development of scales and items of the survey in the quantitative phase: a between-subjects experimental survey (N = 176), where participants were randomly assigned to a scenario featuring either a popular female or a popular male athlete. The methodology focused specifically on measuring the interaction effects between the respondent’s gender and the athlete’s gender to analyze Expertise, Trustworthiness, Attractiveness, Perceived Fit, Gender Connection, Brand Attitude, and Purchase Intention.

Conclusion: The findings show that endorser gender and consumer gender matter most when considered together. Consumers rated same-gender endorsers significantly higher on Gender Connection, which was the strongest predictor of Purchase Intention. Perceived Fit between the athlete and the brand was the strongest predictor of Brand Attitude. Traditional credibility dimensions, namely Expertise, Trustworthiness, and Attractiveness, were related to outcomes but lost their predictive power once Perceived Fit and Gender Connection were included in the model. Authenticity emerged as a gender-neutral baseline expectation across all endorsements. Together, these findings suggest that endorsement effectiveness in sportswear marketing depends less on the athlete’s individual characteristics and more on how well the athlete aligns with both the brand and the consumer.