Gender is a critical factor in managing and mitigating risks to cybersecurity. While the field of cybersecurity has largely ignored this issue, I describe how computing infrastructures are better at protecting the digital resources of men versus women. Research shows that women are more often victims of breaches in online networks and lapses in security systems. Whether through commercial data hacks or identity theft, these events disproportionately affect women’s finances, privacy, and online safety. Women are also targets of gender-specific types of cybercrime, like online harassment and “sextortion.” Such disparities urge us to ask: for whom are cybersecurity infrastructures being built? who is being left out? and why? A socio-technical approach helps us to understand these complex issues and develop more inclusive design strategies for cybersecurity.