- Originea Harului
- Origins
- Orlando
- Orlando Furioso
- Orley Farm
- Orley Farm (Historical Novel)
- Ornella
- Oroonoko
- Orphan Boy
- Orphan Girl
- Orphan of the Olive Tree
- Orphan Train Sweetheart
- Orphans and Angels
- Os Anos de Aprendizado de Wilhelm Meister
- Os desafios de uma dama
- Os desejos do duque
- Os Donos da Terra
- Os Fidalgos da Casa Mourisca
- Os Imperios de Vidro: As Aventuras da Pomba Vermelha
- Os Infortúnios de Lady Lucianna
- Os Lusíadas
- Os MALAVOGLIA
- Os MISERÁVEIS - Victor Hugo
- OS NOIVOS - A. Manzoni
- Os Pecados do Conde - Série “Caçando um Nobre” 2
- Os Perigos Do Amor
- Os Rios Inumeráveis
- Os Rokesbys
- Os Segredos de Mary Bowser
- Os Selvagens Caminhos do Amor
- Os senhores da guerra
- Os sertões: edição crítica comemorativa
- Os últimos dias de Lampião e Maria Bonita
- Oscar and Lucinda
- Oskuld i Paris
- Oskuld i Paris
- Osmanlılar
- Oso Espiritual Jefe
- Osprey Reef
- Othello
- Other Pens, Volume 1
- Other Side of the Line
- Other Than
- Otherwise Engaged
- Otra vez ante el altar
- Otto der Schütz
- Otto der Schütz: Historischer Roman
- Otus in Betulaceæ
- Our Darkest Night
- Our Duty
- Our Emily
- Our Friend the Charlatan
- Our Friends in Berlin
- Our Heroines Suffer a Scandal
- Our Home On Becky's Ridge
- Our Hope Alone (Whitehall Season 1 Episode 10)
- Our Land of Beyond
- Our Mr. Wrenn
- Our Time is Now 2
- Our Time Is Now 4
- Our Time Will Come: War, Separation and a Daring Attempt to Reunite
- Our Wicked Mistake
- Our Woman in Moscow
- Our Yanks
- Ousada debutante
- Out From A Golden Dawn: Four Historical Romance Novellas
- Out From The Badlands: Four Historical Romance Novellas
- Out From the Mists of Time: Four Historical Romances
- Out of a Dream
- Out of Darkness
- Out of Obscurity
- Out of Splinters and Ashes
- Out Of The Ashes
- Out of the Ashes
- Out of the Black Land
- Out Of The Blue
- Out of the Blue (A Regency Time Travel Romance)
- Out of the Dark
- Out of the Embers
- Out of the Ordinary
- Out of the Rain
- Out Of The Shadows Comes Love: Four Historical Romance Novellas
- Out of the Storm (Beacons of Hope)
- Out of Thun
- Out of Time Series Box Set II (Books 4-6)
- Out of Time Series Box Set III (Books 7-9)
- Out Where the Sun Always Shines
- Outback Born
- Outcast Child
- Outcrossing
- Outland
- Outlander
- Ecos do futuro
- Outlaw
- Outlaw in Paradise
- Outlaw Love
- Outlaw Marshal
- Outlaw of Ironguard
- Outlaw Wife
- Outlaw's Secrets
- Outlaw's Son
- Outlawed Love
- Outrageous Confessions Of Lady Deborah