Evidence that gender inequalities and restrictive norms adversely affect health is extensive; however, far less research has focused on testing solutions. We first comprehensively reviewed the peer-reviewed and grey literature for rigorously evaluated programmes that aimed to reduce gender inequality and restrictive gender norms and improve health. We identified four mutually reinforcing factors underpinning change: (1) multisectoral action, (2) multilevel, multistakeholder involvement, (3) diversified programming, and (4) social participation and empowerment. Following this review, because little research has investigated the effects of national-level law and policy reforms, we conducted original quasi-experimental studies on laws and policies related to education, work, and income, all social determinants of health in which deep gender inequalities exist. We examined whether the laws and policies significantly affected health outcomes and gender norms, and whether law-induced and policy-induced changes in gender norms mediated the health effects, in areas for which longitudinal data existed. Laws and policies that made primary education tuition-free (13 intervention countries with the law and/or policy and ten control countries without) and that provided paid maternity and parental leave (seven intervention and 15 control countries) significantly improved women's and their children's health (odds ratios [OR] of 1·16–2·10, depending on health outcome) and gender equality in household decision making (OR 1·46 for tuition-free and 1·45 for paid maternity and parental leave) as a proxy indicator of gender norms. Increased equality partially mediated the positive effects on health outcomes. We conclude by discussing examples of how improved governance can support gender-equitable laws, policies, and programmes, immediate next steps, and future research needs.