Language law in Belgium is based on two concepts. The territoriality principle entails that official language use differs from one linguistic region to another. The constitutional freedom of language is a crucial complement to territoriality and grants residents the right to employ the language of their choice. In the monolingual regions of the country, this fundamental right is, however, restricted to the private domain. In the bilingual region of Brussels-Capital, a freedom of language, restricted to French and Dutch, exists also in the public domain: residents may choose either language to communicate with the authorities. In this article, it is clarified how the Belgian language regime occurred as a result of the interaction between territoriality and freedom of language, already dating back to long before Belgium came into existence. It is claimed that the Belgian model has, in actual fact, served as a tool for peaceful conflict management and has greatly added to preserving language diversity. Yet, at the same time, tensions between the two basic concepts exist and are pointed out in this article.