This chapter explores the linkages between Sustainable Development Goal (SDG) 3 ‘Health’ and SDG 5 ‘Achieve gender equality and empower all women and girls’. We argue that health equity and gender equality are ‘twin forces’ that are historically connected and cannot be separated, creating either strong co-benefits or a ‘double jeopardy’ scenario for health and gender equality. Developments at the cross-roads of SDG 3 and SDG 5 are never ‘gender neutral’ and need attention for two reasons: to strengthen the health policy co-benefits and to prevent and mitigate adverse effects if gender equality is ignored. We introduce a conceptual model of researching co-benefits that expands the focus on macro-level co-benefits towards more complex governance processes and outcomes, including gender mainstreaming approaches. Selected empirical case studies consider major targets of SDG 5 and related SDG 3 sub-goals, illustrating different scenarios of implementation of health and gender co-benefits in a range of policy and governance contexts. The empirical cases illustrate that governance actions and intersectoral structures/institutional pathways shape the ‘windows of opportunity’ for co-benefits, yet co-benefits remain contested and must be re-assured, a lesson most recently learned from the COVID−19 pandemic.