Silesians is a geographical term for the inhabitants of Silesia, a historical region in Central Europe divided by the current national boundaries of Poland, Germany, and the Czech Republic. Historically, the region of Silesia has been inhabited by Polish, Czechs, and by Germans. Therefore, the term Silesian can refer to anyone of these ethnic groups. However, in 1945, great demographic changes occurred in the region as a result of the Potsdam Agreement leaving most of the region ethnically Polish and/or Slavic Upper Silesian. The Silesian dialect is one of the main dialects of the Polish language and based on Polish/Lechitic grammar. The names of Silesia in different languages most likely share their etymology—Polish: ; German: Schlesien pronounced [ˈʃleːzi̯ən] ; Czech: Slezsko ; Lower Silesian: Schläsing; Silesian: Ślōnsk ; Lower Sorbian: Šlazyńska ; Upper Sorbian: Šleska ; Latin, Spanish and English: Silesia; French: Silésie; Dutch: Silezië; Italian: Slesia; Slovak: Sliezsko; Kashubian: Sląsk. The names all relate to the name of a river and mountain in mid-southern Silesia, which served as a place of cult for pagans before Christianization.

Silesian, occasionally called Upper Silesian, is an ethnolect of the Lechitic group spoken by part of people in Upper Silesia. Its vocabulary was significantly influenced by Central German due to the existence of numerous Silesian German speakers in the area prior to World War II and after. The first mentions of Silesian as a distinct lect date back to the 16th century, and the first literature with Silesian characteristics to the 17th century.