During the years of the Estado Novo [New State Regime], relations with UNESCO were marked by intense criticism of Portuguese colonial policy, which led to Portugal’s withdrawal from the organisation in 1972. With the establishment of a democratic regime in Portugal, one that is willing to comply with the rules of the international community, this situation changed. This article focuses on the period from 1974, the year Portugal returned to UNESCO, to 1977, marked by the establishment of a Permanent Mission in Paris. Drawing on relevant bibliography and archival sources, the article aims to analyse: how decolonisation and democratisation were addressed within the United Nations system; the role of the Portuguese Ministry of Foreign Affairs, represented by the minister at the time, Mário Soares, in the re-establishment of relations with the United Nations and UNESCO; the conduct of the process leading to Portugal’s return to the organisation and the main actors involved; and, finally, the first steps taken by the newly created Portuguese Permanent Mission to UNESCO.