| Nova (ES) | Espagne | 2 |
| Nova Fronteira | Brésil | 2 |
| Nova knjiga | Croatie | 1 |
| Novalis | | 4 |
| Novateures | France | 2 |
| Novedi | France | 12 |
| Novedit | France | 7 |
| Novel | France | 25 |
| Novelas | Belgique | 3 |
| Novelcast | France | 2 |
| Novellix | Suède | 6 |
| Novelwright Press | Angleterre | 1 |
| Novice | France | 14 |
| Novo Conceito | Brésil | 2 |
| Nowell | | 1 |
| Nowfuture | | 14 |
| NTC / Contemporary Publishing Company | France | 2 |
| Nube de Tinta | | 11 |
| Nuclea | France | 12 |
| Nueva Nicaragua | Nicaragua | 3 |
| Nuevas ediciones del bolsillo | Espagne | 9 |
| Nui nui | | 33 |
| NuiNui | | 24 |
| Nuit d'Avril | France | 25 |
| Nuits Blanches | France | 2 |
| NUM | Canada | 10 |
| Numeriklivres | France | 256 |
| NumeriPrimi° | France | 1 |
| Numilog | France | 16 |
| Nunavut Arctic College Media | | 5 |
| Nutty Sheep | | 74 |
| Nuvis | France | 1 |
| Nykta | France | 2 |
| NYLA | France | 17 |
| Nymphalis | | 121 |
| NYU Press | | 8 |
| N°1 | France | 21 |
| N°1 / Olivier Orban | France | 6 |
| N°1 / Stock | France | 22 |
| Ô Plaisir | France | 2 |
| O'Brien Press | Irlande | 36 |
| O'Reilly | Etats-Unis | 1 |
| O.D. - Indiens de tous pays | | 4 |
| O.D.E.G.E. | France | 4 |
| O.D.E.J. | France | 32 |
| Obelisco | France | 2 |
| Oberon Books | Angleterre | 5 |
| Objectif Noir | | 2 |
| Objecto Anónimo | Portugal | 1 |
| Obriart | | 9 |
| Observatoire des inégalités | France | 1 |
| Obsidian Mountain Publishing | Etats-Unis | 22 |
| Occident (CH) | Suisse | 1 |
| Océan | France | 36 |
| Oceano | Mexique | 3 |
| OCIM | | 4 |
| ocrée | | 9 |
| Octaedro | Espagne | 4 |
| Octave | Canada | 8 |
| Octobre | France | 47 |
| Octopus | | 14 |
| Octoquill | France | 40 |
| Odé | France | 3 |
| Odepi | France | 1 |
| Odicé | France | 1 |
| Odile Jacob | France | 743 |
| Odin | France | 21 |
| Odyssée | | 2 |
| Odyssey | France | 3 |
| Oeil du Prince | France | 7 |
| Oetinger | Allemagne | 28 |
| Ofelbe | | 85 |
| Off Limits Press | Etats-Unis | 2 |
| Office de publicité | France | 2 |
| Office des Publications Officielles des Communautés Européennes | France | 3 |
| Officina Libraria | Italie | 2 |
| Oficina de Livros | Brésil | 1 |
| Oftomes Publishing | | 1 |
| Ogam-Celticum | France | 1 |
| Ogham | France | 2 |
| Ogmios | | 16 |
| Ogoni | | 3 |
| Oh! | France | 58 |
| Ohdio | Canada | 3 |
| Ohzora Shuppan | Japon | 2 |
| Okama | | 13 |
| Okno | France | 12 |
| Okopix | France | 1 |
| Oktopus | Suisse | 1 |
| Olalde | | 1 |
| Old Mill Press | Etats-Unis | 2 |
| Old Street Publishing | Angleterre | 1 |
| Oldcastle Books | | 4 |
| Oliane | France | 1 |
| Olibris | France | 5 |
| Oliver Heber Books | Etats-Unis | 3 |
| Olivetan | | 5 |
| Olivier Morattel | | 26 |
| Olivier Orban | France | 36 |
| Olivius | France | 4 |
