This research examined a potential mechanism underlying gender differences in math performance by testing a mediation model in which women's higher anxiety taxes their working memory resources, leading to underperformance on a mathematics test. Participants for the 2 studies were college students (N = 87, N = 118) who completed an anxiety measure, 2 working memory tasks (verbal and visuospatial), and a challenging math test including both geometry and algebra items. Findings showed a significant gender difference in math performance, anxiety, and visuospatial working memory. Further, there was a mediating chain from gender to the worry component of anxiety to visuospatial working memory to math performance. The results suggest that women's heightened worry may have utilized their visuospatial working memory resources, and the resulting gender differences in working memory were associated with gender differences on a math test. The present research contributes to our understanding of affective and cognitive factors underlying gender differences in mathematics. The findings are discussed in terms of their implications for interventions aimed at reducing anxiety and improving working memory skills.