- 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
- Oath Keeper
- Ocalił mnie kowal
- Occhi profondo mare
- Ocean Fish School
- 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
- Off to the Wilds, Being the Adventures of Two Brothers
- Oh No! Shark in the Snow!
- Oh, Deer! Christmas Magic
- Old Dragon
- Old English Fairy Tales
- Old Gold or The Cruise of the Brig Jason
- Old Home New Home
- Old Surehand I
- Old Surehand II
- Old Surehand III
- Olive's Perfect World
- Oliver Twist: Audio Edition
- Olivier l'Ours savant
- Ollie and Claire
- Olumurewa’s Plant
- Ombra. Una parabola
- 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 Shoulder of St. Christopher
- Ona
- Once Upon a Magic Book
- Onde - Uomini in viaggio alla ricerca di mondi migliori
- One
- One Boy's Shadow
- 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
- Onslow, or the Adventures of Dick Onslow Among the Redskins
- Oodle The Poodle
- Oogy, the Bald-Headed Owl
- Oozy
- Openiel, Behind the Fans
- Operation Save a Generation
- Operation Tiger
- Opowiadania wszystkie
- Opowieści o Małej Czarownicy Ismie
- Opus Gemini I
- Origin
- Oro
- Ostatni szczegół
- Our Sailors, Gallant Deeds of the British Navy During Queen Victoria's Reign
- Out of Breath (The Lithia Trilogy, Book 1)
- Out of the Ark
- Outside Looking In
- Overdue, The Story of a Missing Ship
- Overheard in Fairyland
- Overworld in Flames
- Owen Hartley, or Ups and Downs, A Tale of Land and Sea
- Owen Tudor (Erzählung) - Vollständige Ausgabe
- Ozma of Oz
- Ozma of Oz (Illustrated Edition)
- Ozma z Krainy Oz