- Oppressed An Arelia LaRue Novel #4
- Oppression
- Opstand
- Opstandeling, Pion, Koning (Over Kronen en Glorie—Boek 4)
- Optimists Die First
- Opętana (Część 12 Wampirzych Dzienników)
- Ora esisti solo tu
- Ora lo sai
- Oracles' Tale
- Orang Ketiga
- Orbis Abenteuer – Ein kleiner Roboter büxt aus
- Order
- Order of the Fallen
- Order of the Wicked
- Ordinul iepurilor regali din Londra
- Orgueil et préjugés
- Orgullo y prejuicio
- Origami Heart
- Origin
- Origin (Lux - Book Four)
- Origin (Saga LUX 4)
- Origins of the Siren Wars
- Origins: Guardian
- Oroonoko
- Orphan Dreamer and the Glass Tattoo
- Orpheus Girl
- Orson's Echoes
- Os dois morrem no final
- Os dois mundos de Astrid Jones
- Os sete da independência
- Oscuro como mi corazón (Colección #BlackBirds)
- Oscuros (Oscuros 1)
- Ossessionata (Libro #12 in Appunti di un Vampiro)
- Other Words for Love
- Otrokyně, Bojovnice, Královna (Koruny A Slávy - Kniha První)
- Otrávená
- Our Broken Pieces
- Our Christmas Spirit: A Holiday Short Story
- Our Frozen Wings
- Our Last Summer
- Our Last Summer Musical
- Our Song
- Our Violent Ends
- Our Wayward Fate
- Our Year in Love and Parties
- Out For Blood: Kula's Destiny (Transylvanica High Series)
- Out Now
- Out of Breath (The Lithia Trilogy, Book 1)
- Out of His League
- Out of Left Field
- Out of His League
- Out of Left Field
- Out of Nowhere
- Out Of Place
- Out of Play
- Out of Sight, Out of Time
- Out of the Dark
- Out of the Sandy Depths
- Out of Tune
- Out There
- Out Walked Mel
- Outcasts
- Over and Over You
- Over Easy
- Over It (The Kiss Off 2)
- Over You
- Overcoming
- Overdrive
- Overlevernes by
- Overspoeld
- Ovunque con te
- Owl Flight
- Owl Kiss
- Own Your Magic Sampler