Mauritius ( (listen) mər-ISH-(ee-)əs, mor-; Bihari languages: मारीशस; French: Maurice [mɔʁis, moʁis] (listen); Mauritian Creole: Moris [moʁis]), officially the Republic of Mauritius, is an island nation in the Indian Ocean about 2,000 kilometres (1,100 nautical miles) off the southeast coast of the African continent, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Agaléga and St. Brandon. The islands of Mauritius and Rodrigues, along with nearby Réunion (a French overseas department), are part of the Mascarene Islands. The main island of Mauritius, where most of the population is concentrated, hosts the capital and largest city, Port Louis. The country spans 2,040 square kilometres (790 sq mi) and has an exclusive economic zone covering 2,300,000 square kilometres (670,000 square nautical miles).

Arab sailors were the first to discover the uninhabited island, around 975, and they called it Dina Arobi. In 1507, Portuguese sailors visited the uninhabited island. The island appears with the Portuguese names Cirne or Do-Cerne on early Portuguese maps. The Dutch took possession in 1598, establishing a succession of short-lived settlements over a period of about 120 years, before abandoning their efforts in 1710. France took control in 1715, renaming it Isle de France. In 1810, the United Kingdom seized the island, and four years later, in the Treaty of Paris, France ceded Mauritius and its dependencies to the United Kingdom. The British colony of Mauritius included Rodrigues, Agaléga, St. Brandon, the Chagos Archipelago, and, until 1906, the Seychelles. Mauritius and France dispute sovereignty over the island of Tromelin as the Treaty of Paris failed to mention it specifically. Mauritius remained a primarily plantation-based colony of the United Kingdom until independence in 1968.

In 1965, the UK split off the Chagos Archipelago from Mauritian territory to the British Indian Ocean Territory (BIOT). The local population was forcibly expelled between 1968 and 1973 and the largest island, Diego Garcia, was leased to the United States. The sovereignty of the Chagos is disputed between Mauritius and the UK. In 2019, the International Court of Justice issued an advisory opinion ordering the UK to return the Chagos Islands to Mauritius, and in 2021, the International Tribunal for the Law of the Sea ruled in support of this, saying that the UK has "no sovereignty over the Chagos Islands".

The island's government is closely modelled on the Westminster parliamentary system and is classified as a full democracy. Mauritius is highly ranked for economic and political freedom with a high-income economy. The country is a welfare state with the government providing universal healthcare, free education up through the tertiary level and free public transportation for students, senior citizens, and the disabled. Owing to its geographic location and centuries of colonialism, the people of Mauritius are highly diverse in ethnicity, culture, language and faith. It is the only country in Africa where Hinduism is the most practised religion. Indo-Mauritians make up the bulk of the population with significant Creole, Sino-Mauritian and Franco-Mauritian minorities.

Along with the other Mascarene Islands, Mauritius is known for its varied flora and fauna. Many species are endemic to the island. The island was the only known home of the dodo, which, along with several other avian species, was made extinct by human activities relatively soon after the island's settlement. There are other endemic animals such as the echo parakeet, the Mauritius kestrel, and the pink pigeon.