This presentation sheds light on the largely overlooked contributions of Catholic lay women to the entangled histories of religion, international relations, and politics in post-World War II Europe and beyond. Historically underrepresented in narratives of international organizations —including within Catholic contexts— these women played a critical yet often invisible role in shaping global debates and policies. Resulting from my ongoing research work in the Roman, French and Belgian archives, this presentation will provide some preliminary outcomes of my MSCA project THEOFEM. Focusing on the engagement of women with leadership positions in international Catholic organizations that operated with institutions such as the United Nations and its specialized agencies, this presentation will explore how these women contributed to key discussions on education, church-state relations, development, and welfare in both colonial and non-colonial contexts. In particular, I will draw on the perspective of entangled history to examine how these lay women's efforts bridged the ecclesial and secular spheres, national and religious boundaries, attempting to influence policies on human dignity, developmental aid, decolonization, and self-determination. By participating in international organizations, these women not only amplified Catholic social teachings but also redefined the concept of the laity, asserting their presence as key actors in global governance. Through diverse case studies, this presentation reveals the plural and significant ways in which these women competed and collaborated with other stakeholders, highlighting their decisive role in shaping some of the twentieth century's most critical processes. By making visible the contributions of Catholic lay women, it underscores the importance of integrating gender and religion into the study of international organizations.