The gender-equality paradox refers to the puzzling finding that societies with more gender equality demonstrate larger gender differences across a range of phenomena, most notably in the proportion of women who pursue degrees in science, technology, engineering, and math. The present investigation demonstrates across two different measures of gender equality that this paradox extends to chess participation (N = 803,485 across 160 countries; age range: 3–100 years), specifically that women participate more often in countries with less gender equality. Previous explanations for the paradox fail to account for this finding. Instead, consistent with the notion that gender equality reflects a generational shift, mediation analyses suggest that the gender-equality paradox in chess is driven by the greater participation of younger players in countries with less gender equality. A curvilinear effect of gender equality on the participation of female players was also found, demonstrating that gender differences in chess participation are largest at the highest and lowest ends of the gender-equality spectrum.