This thesis focuses on the transactions of works of art that took place in Portugal during the period of the Third Reich (1933-1945), the institutions and individuals involved in these transactions, and the works of art that were the object of those transactions. Drawing on American, Austrian, British, Dutch, French, German, Portuguese, and Swiss primary sources, the thesis sets out to determine the extent of the influence of the refugee flux into the country and of the international circulation of Nazi-looted art on the Portuguese art market. It does so by identifying and studying the actions of specific groups identified as having the higher chances of benefiting from these circumstances: importers and exporters of non-contemporary works of art; national art museums in Lisbon and Porto, cities with international communications and transport networks, which hosted the highest number of refugees; public museums in seaside and spa resorts, where thousands of refugees resided during the war years; and the foreign art dealers who opened businesses in Lisbon. Conceptually, it begins with a large universe of analysis, narrowing its scope as the chapters progress, culminating in the study of the actions of one single figure, and clarifying the provenance of one single painting, in a case study that brings together various areas of research examined previously. While findings confirm the supposition that the Portuguese State and public institutions did not knowingly engage in the acquisition of Nazi-looted art during this period, they reveal that some of their acquisitions require further provenance research, and that the actions of specific individuals in bringing works of art into the country demand further scrutiny.