NPO

NPO may refer to:

Medicine

Nil per os, Latin for 'nothing by mouth', a medical instruction to withhold oral intake of food and fluids
neurogenic pulmonary oedema

North Pacific Oscillation, a teleconnection pattern in atmospheric conditions over the North Pacific
NP optimization problem, an optimization problem that is NP-hard
NPO, characterizing thermal stability of a capacitor
The NPO complexity class, standing for "NP-optimization problem", in computational complexity

Nonprofit organization
National Portfolio Organisation, a UK-based culture and arts organisation receiving substantial funding from Arts Council England
National Ports Organisation, former part of the UK Department for Transport
National Preservation Office, part of the British Library
Scientific Production Association (Nauchno-Proizvodstvennoye Obyedineniye, Научно-производственное объединение), a form of scientific research-to-production facility in the Soviet Union and the Russian Federation.
Nederlandse Publieke Omroep ('Netherlands Public Broadcasting'), governing body of the Netherlands (Dutch) Public Broadcasting System
Nederlands Publieke Omroepbestel ('Dutch public broadcasting system'), the public broadcasting service in the Netherlands
Netherlands Pathfinder Organisation (Nederlandse Padvinders Organisatie), one of the organisations that evolved into Scouting Nederland, the national Scouting organisation
NPO UK Ltd., a chain of stationery and book shops in Northern Ireland, now part of Eason & Son
National Printing Office, one of the three recognized government printers of the Philippines
National Parents Organization, non-profit charitable and educational organization in the United States that promotes shared parenting.