Modern Greek (Νέα Ελληνικά, Néa Elliniká, [ˈne.a eliniˈka] or Κοινή Νεοελληνική Γλώσσα, Kiní Neoellinikí Glóssa), generally referred to by speakers simply as Greek (Ελληνικά, Elliniká), refers collectively to the dialects of the Greek language spoken in the modern era, including the official standardized form of the languages sometimes referred to as Standard Modern Greek. The end of the Medieval Greek period and the beginning of Modern Greek is often symbolically assigned to the fall of the Byzantine Empire in 1453, even though that date marks no clear linguistic boundary and many characteristic features of the modern language arose centuries earlier, beginning around the fourth century AD.

During most of the Modern Greek period, the language existed in a situation of diglossia, with regional spoken dialects existing side by side with learned, more archaic written forms, as with the vernacular and learned varieties (Dimotiki and Katharevousa) that co-existed in Greece throughout much of the 19th and 20th centuries.