- Once Upon Now
- Onda d'amore
- One and Only
- One and Only Love : Interracial Romance Collection
- One Autumn Night In Rhine Falls
- One Big Trap
- One Brave Cowboy
- One Christmas Morning, One Summer’s Afternoon
- One Empire Night
- One Fiery Night
- One Friday in Sunflower
- One Hit Wonder (Rock Stars in Love, Book 2)
- One Hot Night
- One Hot SEAL
- One Knight's Stand
- One Lousy Wish
- One Lucky Night
- One Magic Christmas
- One Moment of Change
- One More Christmas - Book Four
- One More Night - Book Two
- One Night
- One Night - Best Friends and Lovers
- One Night at Pemberley: A Pride and Prejudice Sensual Intimate
- One Night in Laguna
- One Night In Paris
- One Night to Forever Box Set: Books 1-4
- One Night to Love
- One Night With Her Husband
- One Night With the Best Man
- One Night with the Sheikh
- One of Those Days
- One of Those Nights
- One On One (WanderLust Lodge Gay Sex Collection)
- One Shot Romance
- One Summer’s Afternoon (Swell Valley Series Short Story)
- One Week in December
- One-Click Buy: July Harlequin Presents
- One-Click Buy: June Harlequin Presents
- One-Click Buy: November Harlequin Presents
- Only a Cowboy Will Do
- Only For Me
- Only for You Bundle (Gay for You Romance)
- Only Home with You
- Only One Lauren: All The Wrong Reasons Season Premiere
- Only One Wish
- Only the Lonely Hearts
- Only You at Christmas
- Ontrouw tot de Dood
- Onverwacht in Parijs
- Onverwachte Wending
- Onyx
- Oops A Rogue Got Me Pregnant! Part 2 - 5 Historical AND Erotic Fertility Short Stories
- Oops A Rogue Got Me Pregnant! Part 1&2 - 10 Historical AND Erotic Fertility Short Stories
- Oops A Rogue Got Me Pregnant! Part 1&2: 10 Historical AND Erotic Fertility Short Stories
- Oops A Rogue Got Me Pregnant!: 5 Historical And Erotic Fertility Short Stories
- Oops He Got Me Pregnant! Complete Series: 20 Erotic Fertility Short Stories
- Oops He Got Me Pregnant! Part 1 & 2: 10 Erotic Fertility Short Stories
- Oops He Got Me Pregnant! Part 2 - 5 Erotic Fertility Short Stories
- Oops He Got Me Pregnant! Part 2: 5 Erotic Fertility Short Stories
- Op Sessie
- Opal
- Open
- Open All Night
- Open Eyes Can't See
- Open Heart Surgery