Recent studies in the history of science call for the historicization of “popular science”, the examination of its multiple aspects in various social and cultural contexts. In accordance with these studies, I will try to show the origins of both the concept and enterprise of the “popularization of science” in Greece in the late 19th century through the periodical press, as well as the relationship between “popularization” and “diffusion” of science. Periodical press was proved very important for the communication of science in late 19th century Greece, in a period when educational, professional and political institutions were under construction. From 1870s scientific knowledge, ideas and practices became accessible to the wide public mainly through the general reader press. At the same period, periodicals of applied science addressing specific audiences emerged. Political, intellectual and scientific elite of the country, motivated by various aims and pursuits, undertook these efforts covered by the general term “diffusion of sciences”. “Diffusion of sciences” was part of a broader project in the social, political and intellectual context of Greece in the second half of the 19th century, declared as “diffusion of useful knowledge”. In this project, both the ideology of progress, seen as moral and intellectual improvement of lay people, and the national ideology, which was epitomized in territorial, economic and cultural dominion of the country in Balkans and near East, were of great importance for shaping the public discourse of science and also being shaped by it. In contrast with the “diffusion of science”, the Greek term that corresponds to the “popularization of science” emerged in the public discourse later, in the early 1890s. However, from the late 1880s few publications arose, that addressed a middle class audience and met with the characteristics of popular science periodicals, although they explicitly aimed at the “diffusion of sciences”. The first to promote “popularization of science” as such were the science professors of the University of Athens, who considered it part of their scientific work and evidence of progress. These professors got involved with the publication of science periodicals and used popularization as vehicle for setting the boundaries of scientific discourse, asking for financial support from the state and pursuing the establishment of a national scientific community.