The Nederlandse Padvinders Organisatie (Netherlands Pathfinder Organisation), one of the Scouting organisiations that evolved into the national Scouting organisation of the Netherlands, Scouting Nederland.

Non-profit organization

NPO, the Nederlandse Publieke Omroep (Netherlands Public Broadcasting) organization.

NPO UK Ltd. was a company which had stationery and book shops around Northern Ireland. However the company was recently bought over by Eason & Son N.I. Ltd.

Научно-производственное объединение (Scientific Production Organization), Russian acronym (for example, NPO Lavochkin)

Nil per os (NPO), Latin for a medical instruction meaning to withhold food and fluids from a patient for various reasons, a shorthand medical term that means "nothing by mouth"

Not to be confused with: NP0 (ends in a zero), a capacitor dielectric material.