- Operation: Midnight Tango
- Operation: Monarch
- Operation: Sand Dune
- Opfertier
- Opposites Attract
- Opposites Attract in Yellowstone
- Optimum - Blutige Rosen
- Opération : bébé menacé - Accusé à tort
- Opération Reddition
- Or3
- Orange Cream Dreams and Murderous Schemes
- Orbital Eclipse: The Second Lunar Lovescape Novel
- Orca
- Orchid Club: Paris
- Order
- Order of Fear
- Order of Protection
- Order of the Blade Boxed Set (Books 1-4)
- Order Of Truth
- Ordinary Evil
- Ordinary People
- Ordonne-moi ! Vol. 1
- Ordonne-moi ! Vol. 2
- Ordonne-moi ! Vol. 3
- Ordonne-moi ! Vol. 4
- Ordonne-moi ! Vol. 5
- Ordonne-moi ! Vol. 6
- Ore Contate
- Oren's Right
- Organic
- Organically Yours
- Orgueil et préjugés
- Orgulloso, desconfiado y... guapísimo (Contigo a cualquier hora 3)
- Orietta
- Origin In Death
- Originals Ride
- Orion's Foot: Myth, Mystery, and Romance in the Amazon
- Orizzonti sconosciuti
- Orlando
- Oro Bizantino
- Orrora
- Orso
- Orte der Erinnerung
- Os bastidores da verdade
- Os estagiários do crime
- Os Fidalgos da Casa Mourisca
- Os Infortúnios de Lady Lucianna
- Os Quatro Amores De Maya
- Oscura fascinación (Barrymore 1)
- Oscuri segreti (eLit)
- Oscuridad en la montaña
- Osiris - the Second Coming
- Osiris 333: Egypt Meets Maya
- Osprey Reef
- Ossessione Alfa
- Ossessione Tormentata
- Ossian
- Ostaggi del tempo
- Ostaggio
- Otage
- Otelo
- Other Side of Love
- Otherwise Engaged
- Otherworld Protector
- Otra vuelta de tuerca
- Oublier Collioure
- Oublier Doc
- Oublier Katie Sheldon
- Oublier pour toujours
- Oui, je le veux ! - L'intégrale
- Oui, je le veux ! – vol. 1
- Oui, je le veux ! – vol. 2
- Oui, je le veux ! – vol. 3
- Oui, je le veux ! – vol. 5
- Oui, je le veux ! – vol. 6
- Our Accidental Baby
- Our Accidental Ride
- Our Accidental Wedding
- Our Destiny
- Our First Embrace
- Our Forever
- Our Friend the Charlatan
- Our Hearts Entwined: Entwined Book One
- Our Hero
- Our Husband
- Our Little Secret
- Our Lives Entwined: Entwined Book Two
- Our Secret Baby
- Our Secret Child
- Our Secret Son
- Our Surprise Baby
- Our Surprise Family
- Our Surprise Wedding
- Our Turn
- Our Unexpected Baby
- Our Unexpected Family
- Our Unexpected Wedding
- Our Universe: Lesbian and Alien Romance
- Our Unlikely Baby
- Our Unlikely Escape
- Our Unlikely Fate
- Our War
- Ourida
- Out for Blood
- Out for Justice (Shotgun Sallys, Book 1)
- Out of Body
- Out of Bondage: BWWM Mafia Romance Novel
- Out of Bondage: BWWM Romance Novel
- Out of Bounds
- Out of Control
- Out of Control
- Out of control
- Out of Control: A Novella, Stolen Hearts Prequel
- Out of Control: Troubleshooters 4
- Out of Darkness 10-Book Bundle
- Out of Darkness to Accepted Love
- Out of Dreams
- Out of Eden
- Out of Exile
- Out of Her League