• Oberon Modern Plays
• Ohio RIS Africa Series
• Ohio RIS Latin America Series
• Ohio RIS Southeast Asia Series
• Ohio Short Histories of Africa
• Oklahoma Western Biographies
• Oktober Verlag
• Once Upon a Time
• Oprah's Book Club
• Ostpreußisches Mosaik
• Other Press
• Outdoor Lives
• Overcoming Adversity
• Oxford India Collection
• Oxford India Paperbacks
• Oxford Portraits
• Oxford Portraits in Science
• Oxford Studies in Byzantium
• Oxford Studies in Modern European Culture
• Oxford Studies in Modern Legal History
• Oxford Studies in Music Theory
• Oxford World's Classics
• Oxford World's Classics (Paperback)
• Oxford in Asia Paperbacks
• Oxford-Warburg Studies