AbstractResearch Question/IssueThis study examines the relationship between boardroom gender diversity reforms (BGDRs) and corporate voluntary disclosure in the form of management earnings forecasts (MEFs) in a sample of 43 countries over the period 2000 to 2020.Research Findings/InsightsTaking advantage of the staggered adoption of the gender diversity reforms that aim to improve women's representation on boards, we find that firms exhibit a greater propensity for and frequency of issuing MEFs. These findings hold for both governance‐based and legislation‐based reforms but are stronger for the latter. Furthermore, we find stronger results (a) when female directors possess higher financial expertise and serve on board sub‐committees, (b) when board activity (meetings and attendance) improved following BGDRs, (c) for firms that had all‐male boards before the reforms and where gender diversity increased shortly after the reforms, and (d) for countries with greater legal enforcement and gender equality. Our findings are robust using the stacked difference‐in‐differences approach and alternative samples, models, and fixed effects. In addition, we find that, after the reforms, there is an increase in the forecast horizon, forecast width, bad news disclosure, accuracy, and the number of disaggregated forecast items.Theoretical/Academic ImplicationsOur study provides the first international and comprehensive evidence of the positive role of board gender reforms in the corporate information environment and offers vital policy implications.Practitioner/Policy ImplicationsOur study informs the ongoing debate regarding the effectiveness of and business case for gender diversity reforms. By documenting a causal link between BGDRs and voluntary disclosure, our study provides important implications for policymakers, regulators, investors, and top management teams.