Samoan (Gagana faʻa Sāmoa or Gagana Sāmoa, pronounced [ŋaˈŋana ˈfaʔa ˈsaːmʊa]) is a Polynesian language spoken by Samoans of the Samoan Islands. Administratively, the islands are split between the sovereign country of Samoa and the United States territory of American Samoa. It is an official language, alongside English, in both jurisdictions. It is widely spoken across the Pacific region, heavily so in New Zealand and in Australia and the United States. Among the Polynesian languages, Samoan is the most widely spoken by a number of native speakers.

Samoan is spoken by approximately 260,000 people in the archipelago and with many Samoans living in diaspora in a number of countries, the total number of speakers worldwide was estimated at 510,000 in 2015. It is the third-most widely spoken language in New Zealand, where 2.2% of the population, 101,900 people, were able to speak it as of 2018.

The language is notable for the phonological differences between formal and informal speech as well as a ceremonial form used in Samoan oratory.

Samoan is an analytic, isolating language and a member of the Austronesian family, and more specifically the Samoic branch of the Polynesian subphylum. It is closely related to other Polynesian languages with many shared cognate words such as aliʻi, ʻava, atua, tapu and numerals as well as in the name of gods in mythology.

Linguists differ somewhat on the way they classify Samoan in relation to the other Polynesian languages. The "traditional" classification, based on shared innovations in grammar and vocabulary, places Samoan with Tokelauan, the Polynesian outlier languages and the languages of Eastern Polynesia, which include Rapanui, Māori, Tahitian and Hawaiian. Nuclear Polynesian and Tongic (the languages of Tonga and Niue) are the major subdivisions of Polynesian under this analysis. A revision by Marck reinterpreted the relationships among Samoan and the outlier languages. In 2008 an analysis, of basic vocabulary only, from the Austronesian Basic Vocabulary Database is contradictory in that while in part it suggests that Tongan and Samoan form a subgroup, the old subgroups Tongic and Nuclear Polynesian are still included in the classification search of the database itself.

There are approximately 470,000 Samoan speakers worldwide, 50 percent of whom live in the Samoan Islands.

Thereafter, the greatest concentration is in New Zealand, where there were 101,937 Samoan speakers at the 2018 census, or 2.2% of the country's population. Samoan is the third-most spoken language in New Zealand after English and Māori.

According to the 2021 census in Australia conducted by the Australian Bureau of Statistics, the Samoan language is spoken in the homes of 49,021 people.