Purpose To examine the associations between gender role discrepancy (non-conformity to socially prescribed masculine gender role norms) and discrepancy stress (distress arising from this discrepancy) on COVID-19 prevention behaviors among men, and the potential moderating effects of race/ethnicity, sexual orientation, and income on these relationships. Design A national online survey was conducted between May and June 2021. Setting The United States. Subjects 749 adult men residing in the United States. Measures A scale measured gender role discrepancy and discrepancy stress. COVID-19 prevention outcomes were constructed and included self-reported vaccination status/intentions, social distancing, mask-wearing, and hand-sanitizing. Analysis Multivariate generalized linear models were performed in SPSS. Results Gender role discrepancy associated with greater odds of vaccination (AOR = 1.35, 95% CI = 1.02-1.78, P = .04), while discrepancy stress associated with lower odds of vaccination (AOR = .48, 95% CI = .35-.68, P < 0. 001) and mask-wearing (AOR = .54, 95% CI = .37-.79, P = .001) for men overall. Discrepancy stress’s negative effect on specific COVID-19 prevention behaviors was only apparent or was amplified for men in lower income brackets (vaccination, social distancing, mask-wearing), racial/ethnic minority men (vaccination), and sexual minority men (social distancing). Conclusion This study demonstrates that gender role discrepancy stress negatively affects men’s engagement in COVID-19 prevention, particularly for men in marginalized populations.