Classical Chinese is the language in which the classics of Chinese literature were written, from c. the 5th century BCE. For millennia thereafter, the written Chinese used in these works was imitated and iterated upon by scholars in a form now called Literary Chinese, which was used for almost all formal writing in China until the early 20th century. Each written character corresponds to a single spoken syllable, and almost always to a single independent word. As a result, the characteristic style of the language is comparatively terse.

Starting in the 2nd century CE, use of Literary Chinese spread to the countries surrounding China, including Vietnam, Korea, Japan, and the Ryukyu Islands, where it represented the only known form of writing. Literary Chinese was adopted as the language of civil administration in these countries, creating what is known as the Sinosphere. Each additionally developed systems of readings and annotations that enabled non-Chinese speakers to interpret Literary Chinese texts in terms of the local vernacular.

While not static throughout its history, its evolution has traditionally been guided by a conservative impulse: many later changes in the varieties of Chinese are not reflected in the literary form. Due to millennia of this evolution, Literary Chinese is only partially intelligible when read or spoken aloud for someone only familiar with modern vernacular forms. Literary Chinese has largely been replaced by written vernacular Chinese among Chinese speakers; speakers of non-Chinese languages have similarly abandoned Literary Chinese in favour of their own local vernaculars. Although varieties of Chinese have diverged in various directions from the Old Chinese words in the Classical lexicon, many cognates can still be found.

There is no universal agreement on the definition of "Classical Chinese". At its core, the term refers to the language used by the classics of Chinese literature roughly from the 5th century BCE to the end of the Han dynasty (202 BCE – 220 CE). The form of Chinese used in works written before the 4th century BCE, like the Five Classics, is distinct from that found in later works. The term "pre-Classical Chinese" is used to distinguish this earlier form from Classical Chinese proper, as it did not inspire later imitation to a comparable degree despite the works' equal importance in the canon.

After the Han dynasty, the divergence of spoken language from the literary form became increasingly apparent. The term "Literary Chinese" has been coined to refer to the later forms of written Chinese in conscious imitation of the classics, with sinologists generally emphasizing distinctions such as the gradual addition of new vocabulary and the erosion of certain points of Classical grammar as their functions were forgotten. Literary Chinese was used in almost all formal and personal writing in China from the end of the Han dynasty until the early 20th century, when it was largely replaced by written vernacular Chinese. The narrower Classical period proper begins with the life of Confucius (551–479 BCE) and ends with the founding of the Qin dynasty in 221 BCE.

The adoption of Chinese literary culture in the Sinosphere amid the existence of various regional vernaculars is an example of diglossia. The coexistence of Literary Chinese and native languages throughout China, Japan, Korea, and Vietnam can be compared to the historical literary use of Latin in Europe, that of Old Church Slavonic in the Eastern Orthodox world, that of Arabic in Persia, or that of Sanskrit and Pali in South and Southeast Asia. However, unlike these examples, written Chinese uses a logography of Chinese characters that are not directly tied to their pronunciation. This lack of a fixed correspondence between writing and reading created a situation where later readings of Classical Chinese texts were able to diverge much further from their originals than occurred in the other literary traditions, adding a unique dimension to the study of Literary Chinese.

Literary Chinese was adopted in Korea, Japan, and Vietnam. The Oxford Handbook of Classical Chinese Literature states that this adoption came mainly from diplomatic and cultural ties with China, while conquest, colonization, and migration played smaller roles. Unlike Latin and Sanskrit, historical Chinese language theory consisted almost exclusively of lexicography, as opposed to the study of grammar and syntax. Such approaches largely arrived with Europeans beginning in the 17th century. Christian missionaries later coined the term 文理 (wénlǐ; 'principles of literature', 'bookish language') to describe Classical Chinese; this term never became widely used among domestic speakers.

According to the traditional "burning of books and burying of scholars" account, in 213 BCE Qin Shi Huang ordered the historical records of all non-Qin states to be burned, along with any literature associated with the Hundred Schools of Thought. The imperial library was destroyed upon the dynasty's collapse in 206 BCE, resulting in a potentially greater loss. Even works from the Classical period that have survived are not known to exist in their original forms, and are attested only in manuscripts copied centuries after their original composition. The "Yiwenzhi" section of the Book of Han (111 CE) is the oldest extant bibliography of Classical Chinese, compiled c. 90 CE; only 6% of its 653 listed works are known to exist in a complete form, with another 6% existing only in fragments.