This article deals with the concept of standard variety based on the idea that each variety reflects the relationships between the relevant social forces in a language community. The author presents and analyzes Ammon's model of social forces determining what is standard in a language. Four forces are identified: the norm authorities, who manage language production, the codifiers, who produce grammars and dictionaries, the model speakers/writers, who produce model texts, and the language experts, who deliver their opinions. What is or is not a variant of the actual standard variety depends on the mutual consensus of all four forces, not only on the decisions of the codifiers themselves. The balance among all four forces guarantees the desirable stability of the standard variety.