This article provides an account of Rómulo de Carvalho's most prominent works on the popularization of science during the Salazarist regime in Portugal. Carvalho has been praised for his "unique" writing style, for his uncommon ability to communicate scientific knowledge with clarity to a wide audience: he wrote to teachers, to secondary students, to the layman and even to the rural peasantry. Most of his books and articles on popularization explored the History and Philosophy of Science, and it has been claimed that he influenced many youngsters to pursue scientific careers. Given the repressive political context imposed by Salazarism, it is argued that Carvalho's work on the popularization of science had a humanist and libertarian connotation. However, intriguingly, different from some of his contemporaries who also promoted humanistic education for all, Carvalho was never targeted by the Dictatorship. The article seeks to shed light on this matter. It points out the educational reach of Carvalho's writings and suggests that popularization of science in repressive regimes is not necessarily a problematic issue as long as it does not threat the status quo.