Nei

Nei or NEI may refer to:
 * Nei, Iran, a village in Ardabil Province, Iran
 * Nei, a character in the Phantasy Star II roleplaying game
 * Nutrition and Education International
 * Nuclear Energy Institute, American nuclear industry lobbying group
 * National Eye Institute, one of the US Institutes of Health
 * Netherlands East-Indies, also known as the Dutch East Indies
 * Northern Engineering Industries, a defunct British engineering firm
 * Noise-equivalent irradiance, in astronomy

People with the name Nei

 * Iivo Nei (born 1931), Estonian chess champion
 * Masatoshi Nei (born 1931), Japanese population geneticist
 * Mati Nei (born 1942), Estonian chess champion
 * Nei Kato, Japanese engineer
 * Nei (footballer, born 1971), born Valdinei Cunha, Brazilian football goalkeeper
 * Nei (footballer, born 1980), born Claudinei Alexandre Aparecido, Brazilian football striker
 * Nei (footballer, born 1985), born Claudinei Cardoso Félix Silva, Brazilian football right-back
 * Nei (footballer, born 1991), born Jozinei João Machado Rodriguez, Brazilian football attacking midfielder
 * Ponto Nei, Japanese VTuber affiliated with Nijisanji