Editura
Orizonturi Noi
Orizonturi Universitare
Orizonturi. Lider
Orizonturi; Cartea pentru toţi
Orizonturi; Editura Ştiinţelor Sociale şi Politice
Orizonturi; Lider
Orizonturi; Luceafărul
Orizonturi; Sirius
Orizonturi; Star
Orizonturi; Ştiinţelor Sociale şi Politice
Orpheus
Orpheus Books Ltd
Orthodoxos Kypseli
Ortodoxia
Osborne; McGraw-Hill
Oscar Print
Oscarmondadori
OSCE/ODIHR; U.S. Department of State; USAID
Osterreichisches Katholisches Bibelwerk
Osutaunu
Osutaunu România
Otaniemi
Otava
Ott Medien GmbH & Co. KG
Ottenheimer Publishers
Otto Hendel
Otto Maier
Otto Maier Ravensburg
Otto von Holten
Ouest
Ouest France
Ouest-France
Ouroboros
Outopos
Oversteps Books
Overture Films LLC
OWH Studio
Oxford University Press
Oxus
Ozalid