PurposeThe paper aims to identify the level of support and expand on the issues recently raised in the literature concerning critical mass theory and board gender diversity (BGD).Design/methodology/approachThe authors systematically searched relevant articles on the Scopus database in March 2024, identifying 132 articles. After removing book chapters, conference papers and reviews, the number was reduced to 122. An additional 16 were discarded as they were irrelevant (e.g. political, theoretical or conceptual) to the current study, leaving a final sample of 106 articles. This longitudinal study covers the period from 2016 to 2024.FindingsThe paper finds compelling evidence supporting the critical mass theory and underscores the importance of corporate BGD in today’s society. It also offers explanations for the few cases where critical mass theory may not be fully supported. It highlights that the performance benefits of corporate BGD, in many cases, only exist when there is a critical mass of female directors on the board.Practical implicationsIt lends support to policymakers in pursuing corporate BGD through quotas, provided that the incentive is not just to fill the numbers.Originality/valueThe paper offers a unique perspective on the level of support for the critical mass theory. It is believed to be the first paper to conduct a longitudinal study to investigate the support for the critical mass theory.