Tuvaluan (/ˌtuːvəˈluːən/), often called Tuvalu, is a Polynesian language closely related to the Ellicean group spoken in Tuvalu. It is more or less distantly related to all other Polynesian languages, such as Hawaiian, Māori, Tahitian, Samoan, Tokelauan and Tongan, and most closely related to the languages spoken on the Polynesian Outliers in Micronesia and Northern and Central Melanesia. Tuvaluan has borrowed considerably from Samoan, the language of Christian missionaries in the late 19th and early 20th centuries.

The population of Tuvalu is approximately 10,645 people (2017 Mini Census), but there are estimated to be more than 13,000 Tuvaluan speakers worldwide. In 2015, it was estimated that more than 3,500 Tuvaluans live in New Zealand, with about half that number born in New Zealand and 65 percent of the Tuvaluan community in New Zealand is able to speak Tuvaluan.

Native speakers of Tuvaluan have various names for their language. In the language itself, it is often referred to as te ggana Tuuvalu which translates to "the Tuvaluan language", or less formally as te ggana a tatou, meaning "our language". The dialects of Vaitupi and Funafuti are together known as a standard language called te 'gana māsani, meaning 'the common language'. Formerly, the country of Tuvalu was known as the Ellice Islands and the Tuvaluan language is also therefore known as Ellice or Ellicean.

Like all other Polynesian languages, Tuvaluan descends from an ancestral language, which historical linguists refer to as "Proto-Polynesian", which was spoken perhaps about 2,000 years ago.

Tuvaluan has had significant contact with Gilbertese, a Micronesian language; Samoan; and, increasingly, English. Gilbertese is spoken natively on Nui, and was important to Tuvaluans when its colonial administration was located in the Gilbert Islands. Samoan was introduced by missionaries, and has had the most impact on the language. During an intense period of colonization throughout Oceania in the nineteenth century, the Tuvaluan language was influenced by Samoan missionary-pastors. In an attempt to "Christianize" Tuvaluans, linguistic promotion of the Samoan language was evident in its use for official government acts and literacy instruction, as well as within the church, until being replaced by the Tuvaluan language in the 1950s.

English's influence has been limited, but is growing. Since gaining political independence in the 1970s, knowledge of the English language has gained importance for economic viability in Tuvalu. The ability to speak English is important for foreign communications and is often the language used in business and governmental settings.

The sound system of Tuvaluan consists of five vowels (/i/, /e/, /a/, /o/, /u/). All vowels come in short and long forms, which are contrastive.

There are no diphthongs so every vowel is sounded separately. Example: taeao 'tomorrow' is pronounced as four separate syllables (ta-e-a-o).