Sino-Tibetan, also cited as Trans-Himalayan in a few sources, is a family of more than 400 languages, second only to Indo-European in number of native speakers. Around 1.4 billion people speak a Sino-Tibetan language. The vast majority of these are the 1.3 billion native speakers of Sinitic languages. Other Sino-Tibetan languages with large numbers of speakers include Burmese and the Tibetic languages. Other languages of the family are spoken in the Himalayas, the Southeast Asian Massif, and the eastern edge of the Tibetan Plateau. Most of these have small speech communities in remote mountain areas, and as such are poorly documented.

The Sinitic languages, often synonymous with the Chinese languages, are a group of East Asian analytic languages that constitute a major branch of the Sino-Tibetan language family. It is frequently proposed that there is a primary split between the Sinitic languages and the rest of the family. This view is rejected by a number of researchers but has found phylogenetic support among others. The Macro-Bai languages, whose classification is difficult, may be an offshoot of Old Chinese and thus Sinitic; otherwise Sinitic is defined only by the many varieties of Chinese unified by a shared historical background, and usage of the term "Sinitic" may reflect the linguistic view that Chinese constitutes a family of distinct languages, rather than variants of a single language.