- O dinossauro mais feroz
- O dinossauro mais feroz / The Most Ferocious Dinosaur (Português e inglês)
- O engenhoso Fidalgo Dom Quixote de la Mancha
- O małpce, która spadła z drzewa
- O preço do sucesso
- Oath Keeper
- Ocalił mnie kowal
- Occhi profondo mare
- Ocean Activity Workbook Age 3-6
- Ocean Fish School
- Ocean Monsters
- Oceania An Odyssey to the Olympic Games
- Oceania An Odyssey to the Olympic Games (for tablet devices)
- OCR A Level History: Britain 1603-1760
- OCR A Level History: England 1485–1603
- OCR Economics AS Student Unit Guides: Unit F582 New Edition The National and International Economy
- Octopus!
- Odio gli italiani
- Odmienna wizja świata
- Odnaleziona odwaga
- Odysseus
- Odyssey of the Outcast
- Of Fire and Brimstone (The Immortal Ones - Elizabeth's Novella)
- Of Unicorns and Leprechauns
- Off To Bed
- Oh No! Shark in the Snow!
- Oh, Deer! Christmas Magic
- Oh, Gott!
- Okker gokker gummi klokker og andre børnerim
- Old Dragon
- Old English Fairy Tales
- Old Home New Home
- Olive's Perfect World
- Oliver Twist, EC
- Oliver Twist: Audio Edition
- Olivier l'Ours savant
- Ollie and Claire
- Oltre il rispetto delle donne
- Olumurewa’s Plant
- Olympe de Gouges : "Non à la discrimination des femmes"
- Ombra. Una parabola
- On a Farm
- On Mother's Day
- On The Balls Of My Feet
- On the Court with ... Jennifer Capriati
- On the Court With... Hakeem Olajuwon
- On the Edge of the Arctic
- On The Go
- On the Shores of the Great Sea
- On the Shoulder of St. Christopher
- Ona
- Once On a Time
- Once Upon a Magic Book
- Onde - Uomini in viaggio alla ricerca di mondi migliori
- One
- One Boy's Shadow
- One Day At Teton Marsh
- One Direction: Who We Are
- One for All and All for One
- One More Dance
- One Night in the Everglades
- One Story A Day: Book 1 for January
- One Year of Sunday School Lessons for Young Children
- Oniria 1 - Le Royaume des rêves, co-édition Hachette/Hildegarde
- Oodle The Poodle
- Oogy, the Bald-Headed Owl
- Oozy
- Opa, du, …?
- Openiel, Behind the Fans
- Operas Every Child Should Know
- Operation Save a Generation
- Operation Tiger
- Opowiadania wszystkie
- Opowieści o Małej Czarownicy Ismie
- Opposites
- Optical Illusions
- Opus Gemini I
- Oranges and Lemons
- Origin
- Oro
- Orphan Among the Irish