The Vatican played an important role in the post-World War II reconstruction of Europe through its collaboration with international aid agencies. This paper draws on newly-opened Vatican archives from the pontificate of Pius XII (1939-1958) and United Nations archives, focusing on the United Nations Relief and Rehabilitation Administration (UNRRA) and the International Refugee Organization (IRO). By combining institutional and bottom-up perspectives, it explores how the Vatican influenced humanitarian policy and practice, working alongside major international organizations to assist displaced persons and other war victims. It highlights the interactions between Church networks and secular aid agencies, uncovering the strategies used by both actors to navigate political and logistical challenges. The findings highlight the Vatican's dual role as both a moral authority and a practical participant in international relief efforts, showing its impact on the shaping of humanitarian narratives and alliances during the early Cold War.