Women remain underrepresented in National Institutes of Health (NIH) study sections, panels of scientists who review grant applications to inform national research priorities and funding allocations. This longitudinal, retrospective study examined the representation of women on study sections before and during the COVID-19 pandemic. Overall, 16,902 reviewers served on 1,045 study sections across 2019, 2020, and 2021, of which 40.1% (n = 6,786) were women. The likelihood of reviewers being women significantly increased from 2019 to 2021, except among chairpersons. Understanding the representation of scientists influencing NIH grant decisions is important to ensuring scientific discovery that meets the nation’s pluralistic needs.