NDA

Military

National Defence Academy (disambiguation)
National Defence Act, legislation for organizing and funding Canada's military
National Defense Area, a military installation at the Mexico–United States border operated by the US Government
Naval Defence Act (disambiguation)
Niger Delta Avengers, a militant group in Nigeria's Niger Delta
Nigerian Defence Academy, a military academy in Nigeria

National Data Administration, a Chinese central government agency
National Democratic Alliance (disambiguation)
National Democratic Assembly, the English name of the Israeli political party Balad

National Dance Alliance, sister company of the National Cheer Association
National Dance Association, defunct association of the American Alliance for Health, Physical Education, Recreation and Dance
National Dental Association, an association for African-American dentists
Net Daemons Associates, a computer network and systems administration company
New Dutch Academy, an orchestra in The Hague, Netherlands
National Disability Authority, an agency of the Irish Department of Children, Disability and Equality
Northern Domestic Airspace, a Canadian aviation organization
Nuclear Decommissioning Authority, an entity of the UK government
National Defense Academy, an armed forces training academy in India.

National Design Awards, awards given by the American National Design Museum
New Drug Application, to get a new drug approved in the United States by the Food and Drug Administration
Non-destructive analysis, a way to evaluate a material's properties without destroying it
Non-disclosure agreement, a legal contract regarding confidentiality
Notre Dame Academy, Patna, a girls' Roman Catholic secondary school in Patna, India
Najran Domestic Airport, an airport in Najran, Saudi Arabia
Nicolas Dupont-Aignan, a French politician
Nico di Angelo, a character from Rick Riordan's Percy Jackson series