Ten countries have established quotas for female representation on publicly traded corporate and/or state-owned enterprise boards of directors, ranging from 33 to 50 %, with various sanctions. Fifteen other countries have introduced non-binding gender quotas in their corporate governance codes enforcing a “comply or explain” principle. Countless other countries’ leaders and policy groups are in the process of debating, developing, and approving legislation around gender quotas in boards. Taken together, gender quota legislation significantly impacts the composition of boards of directors and thus the strategic direction of these publicly traded and state-owned enterprises. This article outlines an integrated model of three institutional factors that explain the establishment of board of directors gender quota legislation based on the premise that the country’s institutional environment co-evolves with gender corporate policies. We argue that these three key institutional factors are female labor market and gendered welfare state provisions, left-leaning political government coalitions, and path-dependent policy initiatives for gender equality, both in the public realm as well as in the corporate domain. We discuss implications of our conceptual model and empirical findings for theory, practice, policy, and future research. These include the adoption and penalty design of board diversity practices into corporate practices, bottom-up approaches from firm to country-level gender board initiatives, hard versus soft regulation, the leading role of Norway and its isomorphic effects, the likelihood of engaging in decoupling, the role of business leaders, and the transnational and international reaction to board diversity initiatives.