In recent years, national governments have started to use the Women, Peace and Security (WPS) agenda to advocate for increasing women’s participation in national militaries. This has raised questions regarding women’s potential impact on compliance with international humanitarian law (IHL). In this article, we examine existing evidence and arguments on the potential impact of women’s increased participation in national militaries and decision-making on international security and IHL compliance. We find some theoretical support for the idea that increasing the participation of women in the national security sector and national militaries may lead to increased IHL compliance through the prioritization of non-violent policies and improved decision-making. However, a substantive body of research on the limits imposed by the substantive gendering of institutions and idealization of masculine traits and practices calls women’s potential impact on IHL compliance into question.