- Osito Tomás se muda a la gran ciudad
- Osito Tomás se va de vacaciones
- Osito Tomás vista la oficina de papá
- Osito Tomás y el festival deportivo intercolegial
- Osito Tomás y el fin de cursos
- Oskar
- Oskar - Ein Kater mit Charakter
- Oskar kommt drauf
- Oskar und Hannes
- Oskiwaddlemunchabunch
- Osoboy, Wonder Dog of the Jungle
- Ossessionata (Libro #12 in Appunti di un Vampiro)
- Ostatni
- Ostatni szlak Cykl Legendy Doliny Ohio. Część 3
- Ostatnia z bajek
- Ostereier
- Osterfest im Streichelzoo
- Ostraffad
- Ostrich
- Ostrich Boys
- Ostriches
- Ostrov na konci všeho
- Ostrov zasvěcení
- Osud
- Osud Draků (Sága Čarodějův Prsten – Kniha Třetí)
- Oswald Bastable and Others
- Oswald, Feline Adventurer
- Osztályharc
- Osíris Bahr E A Torre Central
- Ot's Ordeal
- Otage de la nuit - Le roman du film Netflix : les pages de l'angoisse - Dès 11 ans
- Otages de la nature
- Otchłań ciągnie
- Othello (Shakespeare For Everyone Else #2)
- Other Boys
- Other Broken Things
- Other Girls Are So Pretty
- Other People's County
- Other People's Money
- Other Times, Other Spaces: A Short Story Collection
- Other Words for Home
- Other Words for Love
- Other Words for Smoke
- Other Worlds
- Other Worlds Than These
- Otherbound
- OtherEarth
- Othergirl
- Otherkin
- OtherLife
- Otherplace
- Others See Us
- Otherwise Known as Pig
- Otherwise Known as Possum
- Otherwise Known as Sheila the Great
- Otherworld
- Otherworld Chronicles #2: The Seven Swords
- Otherworld Chronicles #3: The Dragon King
- Otherworld Chronicles: The Invisible Tower
- Otherworlds - Tome 1
- Otho the Archer
- Otis
- OTIS ADELBERT KLINE Ultimate Collection: Science-Fantasy Classics, Sword & Sorcery Tales
- Otis Grows
- Otis Spofford
- Otogizoshi
- Otopia
- Otra Luz
- Otra vez el Santo
- Otrokyně, Bojovnice, Královna (Koruny A Slávy - Kniha První)
- Otromundo
- Otrávená
- Ottilie en de monstermacht / 2
- Otto
- Otto and the Hunt for Mal Goue
- Otto giorni in una soffitta
- Otto ist einsam
- Otto Osterhase hat keinen Bock
- Otto P. Nudd
- Otto Tattercoat and the Forest of Lost Things
- Otílio, o pinguim
- Ouch
- Oudste
- Oufti et le roi Houtsiplou
- Oudste
- Oufti et le roi Houtsiplou
- Ouija II. Il riflesso del male
- Ouitalos
- Oum Malep
- Ouoro le chimpanzé
- Oups, mauvaise fenêtre
- Our American Adventure — Publix Press
- Our American Cousin
- Our Australian Girl
- Our Australian Girl: Marly walks on the Moon (Book 4)
- Our Australian Girl: Marly's Business (Book 2)
- Our Australian Girl: Meet Marly (Book 1)
- Our Australian Girl: Meet Pearlie (Book 1)
- Our Batak House
- Our Best Jokes
- Our Black History Projects
- Our Boys
- Our Broken Pieces
- Our Brothers at the Bottom of the Bottom of the Sea
- Our Castle by the Sea
- Our Christmas Spirit: A Holiday Short Story
- Our Class Wants Perfect Attendance! Mousey, Where Are You?
- Our Crooked Hearts
- Our Dark Duet
- Our Family
- Our Favourite Fairy Tales
- Our First Blizzard Snowman
- Our Fourth Gift
- Our Frank
- Our Friends, the Frogs
- Our Frozen Wings
- Our Funny Dunny
- Our Glorious Empire
- Our Gods Wear Spandex
- Our Happy Heart
- Our Home in the Silver West
- Our House
- Our House 2: Time to Shine
- Our Invisible Friend
- Our Lady of Mysterious Ailments