An orthography is a standardized system for using a particular writing system (script) to write a particular language. It includes rules of spelling, and may also concern other elements of the written language such as punctuation and capitalization.

Most significant languages in the modern era are written down, and for most such languages a standard orthography has 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. If a language uses multiple writing systems, it may have distinct orthographies, as is the case with Kurdish, Uyghur, Serbian, Inuktitut and Turkish. 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 through less formal processes.

Orthography is distinct from typography, which is concerned with principles of typesetting.