Rusyn /ˈruːsᵻn/ (Rusyn: русиньска бесїда or русиньскый язык), also known in English as Ruthene UK /rʊˈθiːn/ US /ruːˈθiːn/ (sometimes Ruthenian), is an East Slavic language variety spoken by the Rusyns of Eastern Europe.

There are controversial political implications about the nature of Rusyn as a language or dialect. Some linguists treat it as a distinct language (with its own ISO 639-3 code), whereas some Ukrainian scholars of Slavic languages treat it as a dialect of Ukrainian.