- Oliver Blue à l’École des Prophètes (Tomes 2 et 3)
- Oliver Blue à l’École des Prophètes (Tomes 3 et 4)
- Oliver Twist
- Olivia Nibblesqueak's Messy Mischief
- Olivia The Orchid Fairy
- Olivia y el gatito perdido (Θlivia 2)
- Olivia y el gran desfile (Θlivia 1)
- Olivia y su nueva amiga (Θlivia 3)
- Olivia's Adventures
- Olla pirata
- Ollie
- Ollie and Lola's Woodland Adventure
- Ollie and the comet
- Ollie and the eclipse
- Ollie's Chance
- Ollie's Odyssey
- Ollie’s Adventures
- Olly's Zoo
- Olympia the Games Fairy
- Olympic Flame Chase
- Omar el niño cangrejo
- Omega City
- Omega City: Infinity Base
- Omega City: The Forbidden Fortress
- Omnia
- On a Summer's Night
- On Gramma’s Rocker
- On Her Majesty's Secret Service
- On Ice: Exploring the Arctic with a Polar Bear Cub (#5)
- On the Edge of the Dark Sea of Darkness
- On The Flip Side
- On the Freedom Trail #4
- Chasing the Falconers (On the Run #1)
- The Fugitive Factor (On the Run #2)
- Now You See Them, Now You Don't (On the Run #3)
- The Stowaway Solution (On the Run #4)
- Public Enemies (On the Run #5)
- Hunting the Hunter (On the Run #6)
- On the way to Nana’s
- On Top of the World
- On vas, Jotu?
- Once Upon a Forest
- Once Upon a Magic Book
- Once Upon a Midnight Eerie
- Once Upon Another Time
- Onde Moram as Casas
- Ondine lovely mermaid
- One Came Home
- One Hundred Bones
- One Plus One Equals Three
- One Step At A Time
- One Tooth Tim & Pirate Jim
- One-Day-Friends
- Ongi etorri harkaitz zekenera
- Only You Can Save Mankind
- Onnen Visser (Historischer Roman)
- Onnen Visser: Der Schmugglersohn von Norderney (Historischer Abenteuerroman)
- Oopsie - I forgot!
- Op klaarlichte dag
- Opa müffelt, Oma schnarcht
- Opa und die Nacht der Wölfe
- Opal Moonbaby and the Best Friend Project (Book 1)
- Opal Moonbaby and the Out of this World Adventure
- Opdagerklubben (1) - Skumfidusmaskinen
- Opdagerklubben (2) - Skildpaddekanonen
- Opdagerklubben (3) - Papegøjehelikopteren
- Opdagerklubben (4) - Snefræserduellen
- Open Animals Day
- Opening Day at the Track
- Aventura Total - Operació rescat
- Operación Miss Bombón
- Aventura Total - Operación rescate
- Operación San Valentín
- Operation Get Rid of Mom's New Boyfriend
- Operation: Candy Bowl
- Operation: Secret Recipe (Geronimo Stilton #66)
- Opowiadania z dreszczykiem
- Opowiadania z kluczem
- Oracle of Doom (The Library Book 3)
- Oranges in No Man's Land
- Orangey the Goldfish: Orangey Goes to School (Book 4)
- Orched
- Order of the Majestic
- Ordinary Magic
- Order of the Majestic
- Ordinary Magic
- Orla the Inventor Fairy
- Orphan of Destiny
- Orphée et la force du chant
- Os Aventureiros e O Mapa Secreto
- Os Aventureiros e O Mistério da Arrábida
- Os Aventureiros e O Segredo do Ouro Negro
- Os Aventureiros Na Cidade Flutuante
- Os cabelos de Crisálida
- Os cabelos de Sara
- Os caçadores de lendas
- Os Contos de Beedle o Bardo
- Os gêmeos Templeton têm uma ideia
- Os manuscritos encantados da senhora Trampolim
- Os meus maís terribles pasadelos
- Os nerds
- Os Náufragos de Bornéu
- Os piratinhas do bem
- Os piratinhas do bem - No mundo da imaginação
- Os piratinhas do bem - No mundo das diferenças
- Os Piratinhas do Bem na Terra dos Gigantes da Amazônia
- Os Piratinhas do Bem Navegando Pela Amazônia
- Os Segredos dos Dragões
- Os tigres de Mompracem
- Turma da Mônica Jovem - Os Três Mosqueteiros
- Os Ziskisitos e o Flecha Vermelha
- Oscar Hazelnut and the Metal Dogtectors
- Oscar The Lovable Seagull
- Oscura luz del monte
- Osiris Saluki
- Osito Ama los Dulces
- Ospira the Savage Sorceress
- Ossiron the Fleshless Killer
- Ostatnie piętro
- Osterspaziergang
- Othello & Giovanni – Chaos auf der Katzenschau
- Othello & Giovanni – Der große Katzen-Raub
- Otherwise Known as Sheila the Great
- Otte tusser og en kat
- Otter Chaos - The Dam Busters