ONU

ONU may refer to:
 * United Nations in other languages, e.g. French Organisation des Nations Unies, Spanish Organización de las Naciones Unidas and Portuguese Organização das Nações Unidas
 * Olivet Nazarene University
 * Ohio Northern University
 * Optical Network Unit, the IEEE term for Optical Network Terminal
 * Order of Nunavut
 * Organizacion de Narcotraficantes Unidos, a Puerto Rican criminal organization
 * Onu (pronoun), Polish neopronoun