- One Truth, No Lie
- One Try
- One Was Lost
- One Way Or Another
- One White Dolphin
- One Whole and Perfect Day
- One Winter Day
- One Wish
- One Wish Away
- One Witch at a Time
- One Woman's Life
- One Word
- One Year at Ellsmere
- One Year in Coal Harbor
- One Year Later
- One Yellow Fish
- One! Hundred! Demons!
- One-Third Nerd
- Onebird: The Rise of Moo
- Onendlech Léift
- Onibi: Diary of a Yokai Ghost Hunter
- Onkel Peppi und andere Geschichten
- Onkel Toms Hütte
- Online Dating: Master The Art of Internet Dating: Create The Best Profile, Choose The Right Pictures...
- Only a Breath Apart
- Only A Phase, Ma: A Gallery of Oddities Story
- Only An Irish Boy
- Only an Irish Girl
- Only Child?
- Only Emma
- Only Ever Always
- Only Everything
- Only For Now
- Only Girls Allowed
- Only If You Can Find Me
- Only If You Dare
- Only Lonely Moany Mona
- Only Mostly Devastated
- Only Remembered
- Only So Big
- Only the Bold (The Way of Steel—Book 4)
- Only the Destined (The Way of Steel—Book 3)
- Only the Moon Howls
- Only the Ocean
- Only the Stars Know Her Name
- Only the Valiant (The Way of Steel—Book 2)
- Only the Worthy (The Way of Steel—Book 1)
- Only When it Rains
- Only You, Sierra
- Onnelin ja Annelin talo
- Ontika
- Onurun Bedeli (Krallar ve Büyücüler—3. Kitap)
- Onyeka and the Academy of the Sun
- Onyx (Saga LUX 2)
- Onyx Elixir
- Onze Reis
- Onzichtbaar
- Oníris
- Oníris - A dádiva dos deuses
- Oolie and the Fox
- Oops
- Ooshu, Dorothy, And The Old Lady
- Op zoek naar de Dionsaurus (dinosaurus kinderboek)
- Op-Op, the Triceratops
- Opa Meume und ich
- Opa's Christmas Collection
- Opa's Halloween Handful
- Opal (Saga LUX 3)
- Opala
- Opaque: Scion Saga Book 1
- Opasno ljeto u Mumindolu
- Open Court
- Open Fire
- Open If You Dare
- Open Mic Night at Westminster Cemetery