An orthography is a set of conventions for writing a language. It includes rules of spelling, hyphenation, capitalization, word breaks, emphasis, and punctuation.

Most significant languages in the modern era are written down, and for most such languages a standard orthography has been developed, often based on a standard variety of the language, and thus exhibiting less dialect variation than the spoken language. Sometimes there may be variation in a language's orthography, as between American and British spelling in the case of English orthography. In some cases orthography is regulated by bodies such as language academies, although for many languages (including English) there are no such authorities, and orthography develops in a more organic way.