Emily will be discussing how the early International Conference of Women Engineers and Scientists (ICWES) meetings grew out of the earlier collective action of women in national settings, particularly in the form of societies for women engineers. She will then talk us through how the conferences built upon, and were situated within, a wider context of women’s collective action, namely peace movements and networks, positing that they ultimately created a distinct form of women-led scientific diplomacy in the second half of the twentieth century.