Abstract: With the rise of Wikipedia as a first-stop source for scientific knowledge, it is important to compare its representation of that knowledge to that of the academic literature. This article approaches such a comparison through academic references made within the worlds 50 largest Wikipedias. Previous studies have raised concerns that Wikipedia editors may simply use the most easily accessible academic sources rather than sources of the highest academic status. We test this claim by identifying the 250 most heavily used journals in each of 26 research fields (4,721 journals, 19.4M articles in total) indexed by the Scopus database, and modeling whether topic, academic status, and accessibility make articles from these journals more or less likely to be referenced on Wikipedia. We find that, controlling for field and impact factor, the odds that an open access journal is referenced on the English Wikipedia are 47% higher compared to closed access journals. Moreover, in most of the worlds Wikipedias a journals high status (impact factor) and accessibility (open access policy) both greatly increase the probability of referencing. Among the implications of this study is that the chief effect of open access policies may be to significantly amplify the diffusion of science, through an intermediary like Wikipedia, to a broad public audience.