This paper proposes theorising gender through complementary sets of behavioural prescriptions or norms rather than by a focus on women (and men). It posits the idea that gender is integral to a disciplinary regime aimed at producing social order, with masculinity at its centre. What appear as advantages to men simultaneously pressure them into conforming to their cultural and socio-economic group’s notions of masculinity including exerting control over wives and offspring. Four complementary foundational norms for both sexes are identified. They evolved during the nineteenth-century in industrialised Europe and were spread to the global south first through Christianisation and colonialism and later through gender and development programmes and mass/social media. These norms are first economic support for sustaining material life versus social reproduction and caring; secondly, male disciplining of (submissive) wives and children; thirdly heterosexuality, marriage and the biological production of children; and fourthly men’s protection of vulnerable women and their ascriptive (ethnic/religious) group for the context, as also the state. These do not determine behaviour but oblige everyone to consider them in negotiating their own conduct, with the most insecure interpreting them most narrowly. The ideology of masculinism supports the regime at the macro level, while also influencing individual behaviour at grassroots. Drawing on cases from my work in Latin America and Sub-Saharan Africa, I show how this functions in practice in relation to how men treat each other and how it impinges on familial gender relations, with particular emphasis on Sub-Saharan Africa, and especially Kaduna, Nigeria. I also discuss how supporting men to delink their behaviour from the norms of masculinity (thus defying masculinism) can make a positive contribution to family life and I posit the importance of further research on the effects of the norms for both sexes to improve our understanding of the functioning of gender.