This study investigates the social media self-presentation of Chinese, South Korean, and US athletes during the 2020 Tokyo Olympics, with the aim of elucidating the influence of gender and nationalism on their online portrayals across countries. A total of 1800 photographs posted by 278 Olympians were analyzed, revealing that (a) South Korean athletes, particularly males, display a higher prevalence of business-related images in their self-presentation compared to athletes from other countries; (b) Chinese athletes exhibit a greater degree of nationalism in their posted photographs than their South Korean and US counterparts; and (c) female athletes, although gaining agency over their online presence, still demonstrate behaviors reinforcing conventional gender norms. This research underscores the multifaceted interplay of gender, nationalistic, cultural, political, and ideological factors in shaping athletes’ self-representations on social media, offering valuable insights into the complex dynamics that inform their digital self-expression.