| Abbreviation | Definition |
|---|---|
| NFU-UNF | National Farmers Union-Union Nationale des Fermiers |
| NFWU | Namibia Farm Workers Union |
| NFWU | National Federation of Workers Unions |
| NGSU | Nationwide Group Staff Union |
| NHISA | National Health Interview Survey Association |
| NHRU | Newcastle and Hunter Rugby Union |
| NHUL | New Hampshire Union Leader |
| NIBU | NORTHERN IRELAND BRIDGE UNION |
| NICU | North Island Credit Union |
| NICU | Northern Inland Credit Union |
| NIPSA | Northern Ireland Public Service Alliance |
| NISU | North Island Students Union |
| NISU | North Island Students' Union |
| NITU | Non Industrial Trade Union |
| NJCS | National Joint Committee for Steel |
| NJNU | New Jersey Nurses Union |
| NLA | National Labor Alliance |
| NLC | Nigeria Labour Congress |
| NLP | National League of Postmasters |
| NLU | National Labor Union |