Norwegian (endonym: norsk [ˈnɔʂːk] ^ⓘ) is a North Germanic language from the Indo-European language family spoken mainly in Norway, where it is an official language. Along with Swedish and Danish, Norwegian forms a dialect continuum of more or less mutually intelligible local and regional varieties; some Norwegian and Swedish dialects, in particular, are very close. These Scandinavian languages, together with Faroese and Icelandic as well as some extinct languages, constitute the North Germanic languages. Faroese and Icelandic are not mutually intelligible with Norwegian in their spoken form because continental Scandinavian has diverged from them. While the two Germanic languages with the greatest numbers of speakers, English and German, have close similarities with Norwegian, neither is mutually intelligible with it. Norwegian is a descendant of Old Norse, the common language of the Germanic peoples living in Scandinavia during the Viking Age.

Today there are two official forms of written Norwegian, Bokmål (Riksmål) and Nynorsk (Landsmål), each with its own variants. Bokmål developed from the Dano-Norwegian language that replaced Middle Norwegian as the elite language after the union of Denmark–Norway in the 16th and 17th centuries and then evolved in Norway, while Nynorsk was developed based upon a collective of spoken Norwegian dialects. Norwegian is one of the two official languages in Norway, along with Sámi, a group of Finno-Ugric languages spoken by less than one percent of the population. Norwegian is one of the working languages of the Nordic Council. Under the Nordic Language Convention, citizens of the Nordic countries who speak Norwegian have the opportunity to use it when interacting with official bodies in other Nordic countries without being liable for any interpretation or translation costs.

Like most of the languages in Europe, Norwegian derives from Proto-Indo-European. As early Indo-Europeans spread across Europe, they became isolated from each other and new languages developed. In northwest Europe, the Germanic languages evolved, further branching off into the North Germanic languages, of which Norwegian is one.

Proto-Norse is thought to have evolved as a northern dialect of Proto-Germanic during the first centuries AD in what is today Southern Sweden. It is the earliest stage of a characteristically North Germanic language, and the language attested in the Elder Futhark inscriptions, the oldest form of the runic alphabets. A number of inscriptions are memorials to the dead, while others are magical in content. The oldest are carved on loose objects, while later ones are chiseled in runestones. They are the oldest written record of any Germanic language.

Around 800 AD, the script was simplified to the Younger Futhark, and inscriptions became more abundant. At the same time, the beginning of the Viking Age led to the spread of Old Norse to Iceland, Greenland, and the Faroe Islands. Viking colonies also existed in parts of the British Isles, France (Normandy), North America, and Kievan Rus. In all of these places except Iceland and the Faroes, Old Norse speakers went extinct or were absorbed into the local population.

Around 1030, Christianity came to Scandinavia, bringing with it an influx of Latin borrowings and the Latin alphabet. These new words were related to church practices and ceremonies, although many other loanwords related to general culture also entered the language.

The Scandinavian languages at this time are not considered to be separate languages, although there were minor differences among what are customarily called Old Icelandic, Old Norwegian, Old Gutnish, Old Danish, and Old Swedish.

The economic and political dominance of the Hanseatic League between 1250 and 1450 in the main Scandinavian cities brought large Middle Low German–speaking populations to Norway. The influence of their language on Scandinavian is comparable with that of French on English after the Norman conquest.