Aktiengesellschaft (German pronunciation: [ˈaktsiənɡəzɛlʃaft]; abbreviated AG) is a German term that refers to a corporation that is limited by shares, i.e., owned by shareholders, and may be traded on a stock market. The term is used in Germany, Austria and Switzerland. It is also used occasionally in Luxembourg (though the French-language equivalent, Société Anonyme, is more common) and for companies incorporated in the German-speaking region of Belgium.

The German word Aktiengesellschaft is a compound noun made up of two elements: Aktien meaning shares, and Gesellschaft meaning society, or, in this context, company. Other types of German companies also have shares, although these shares are called Anteile rather than Aktien. A similar distinction exists in other languages; for example, in Polish the two types of share are called akcja and udział, or in Spanish, acción and cuota.

In Germany and Austria, the legal basis of the AG is the respective Aktiengesetz (abbr. AktG). In Switzerland, it is contained within the Obligationenrecht (OR). The law^[where?] requires all corporations to specify their legal form in their name which tells the public their limitation of liability, all German (required by § 4 Aktiengesetz) and Austrian stock corporations include Aktiengesellschaft or AG as part of their name, frequently as a suffix.