Twenty years have passed since a group of young linguists whose work deals with the study of Slavic languages founded "Polyslav" at the University of Konstanz (Germany). Ever since, the Polyslav meetings have been held at a Central or Eastern European university. From 6-8 September 2016, the 20th Annual International Academic Conference of the Polyslav Association (Polyslav XX) was held in Moscow (Russia). This jubilee conference was co-organized by the Moscow State Pedagogical University and the Institute for Slavic Studies of the Russian Academy of Sciences. Polyslav XX was attended by 37 participants from eight countries - most of them from Russia and Poland, but also from the Czech Republic, Germany, Hungary, Lithuania, Serbia, and Ukraine. The present proceedings contain 20 papers in four Slavic languages (Russian, Polish, Ukrainian, and Slovene), two in English, and one in German. All 23 contributions meet the basic publishing standards and international editorial conventions, including a double-blind review. In total, 29 reviewers from Europe and the USA guarantee the academic level of the published papers.