The Malay world or Malay realm (Indonesian/Malay: Dunia Melayu or Alam Melayu) or Malaysphere is a political concept or an expression that has been used by different authors and groups over time to denote several different notions, derived from varied interpretations of 'Malay' either as an ethnic group, as a racial category, as a linguistic group or as a cultural group. The use of the term Malay in much of the conceptualisation is largely based on the prevalent Malay cultural influence, manifested in particular through the spread of the Malay language in Southeast Asia as observed by different colonial powers during the Age of Discovery and spread of Islam. The term remains highly controversial in Indonesia and outside the Malay-speaking areas, because it is considered politically charged and irredentist rather than purely cultural.
The concept in its broadest territorial stretch may apply to a region synonymous with Austronesia, homeland to the Austronesian peoples, that extends from Easter Island in the east to Madagascar in the west. Such description has its origin in the introduction of the term Malay race in the late 18th century that has been popularised by orientalists to describe the Austronesian peoples. In the development of further research, the Malay race was categorized as a Malayo-Polynesian languages. In a narrower sense, the Malay world has been used as a synonym for Malay sprachraum, referring to the Malay-speaking countries and territories of Southeast Asia, where different standards of Malay are the national languages or a variety of it is an important minority language. The term in this sense encompasses Brunei, Indonesia, Malaysia, Singapore and Southern Thailand, and is sometimes used interchangeably with the concepts of 'Malay Archipelago' and 'Nusantara'.