- Unknown Science Stories
- Unkontrollierbare Sprünge
- UNLAWFUL RESTRAINT
- Unleashing A Warrior
- Unleashing the Gods
- Unlikely
- Unlikely Heroes
- Unlocked
- UNMADE
- Unmoored
- Unnatural Selection
- Unnatural Selexion
- Unnecessary Treasures: Uncommon Synths
- Uno Splendido Futuro
- Unparalleled Affairs
- Unplugged
- Unraptured
- Unraveled in Space - A Sexy Romance Sci-Fi Short Story Featuring BDSM & Bondage from Steam Books
- Unrequited Death
- Unseemly Science
- Unseen Demons
- Unseen Forces
- Unseen Servant
- Unseen—Unfeared and Other Stories
- Unsettled
- Unsettling Times
- Unshaken
- Unsichtbare Freunde und Feinde
- Unsterblich
- Unsterblich - Tor der Ewigkeit
- Unstoppable
- Untamed: A Forbidden Love Survival Adventure
- Unter dem Banner des weißen Hirsches
- Unter dem Mondstern
- Unter den Masken
- Unter der alten Erde
- Unter der Sonne
- Unter fremden Sternen - Die Frontier-Saga (2)
- Unter Qualen
- Unter Toten 2
- Unter Toten 3
- Unter Unter den Linden: Dystopie
- Untermieter
- Unternehmen Proteus
- Unternehmen Tiefsee
- Unterwerfung
- Untethered
- Until All the Stars Are Found
- Until the Dawn (Sandes Chronicles #3)
- Until the End
- Until the Last Dog Dies
- Until the Last of Me
- Until the Little Birds Sing
- Untimely
- Untitled Bruce Lee/Phil Dick Project
- Untrained Fascination
- Unusual Mate : Sci-Fi Alien Romance Collection
- Unverschlüsselt
- Unwilling
- Unwinding the Serpent
- Unworthy Heroes
- Unwrapped Sky
- Unyielding
- Uomini della Morte
- Uomini troppo veri
- Up In Flames
- Up in the Air
- Up Jim River
- Up the Line
- Up the Walls of the World
- Upadła Świątynia
- Upgrades - Episode VII
- Uploaded on the 4th of July
- Upon Another Edge Broken
- Upon The Dull Earth
- Upon the Lonesome Wild
- Upon This Rock
- Upon This Rock: Book 3 — Consider Pipnonia
- Upon This Rock: Compilation
- Uppity Aliens
- Upon This Rock: Compilation
- Uppity Aliens
- Upsetting the Balance (Worldwar, Book Three)
- Upside - Book One
- Upsidonia
- Upstairs
- Upstart Mystique
- UR 2306
- Uranus
- URAR: Novela (Hrvatsko Izdanje)
- Urar: novela (Slovenska izdaja)
- Urban Heroes
- Uriel: Libro Primero Gnostic Moly
- Urland
- Urmageren: en novelle (Dansk udgave)
- Urmakaren: en novellett (Svenska utgåvan)
- Urmakarens Verk
- Urmakarens värld
- Urmakeren: en novella (Norsk utgave)
- Ursprung 357
- Ursula K. Le Guin: Always Coming Home (LOA #315)
- Urth
- Usagers Cursifs
- Use of Weapons
- Used Aliens
- Userland – Berlin 2069
- Using Her Body To Capture the Alien
- USS Krakowski
- Utan vingar
- Utopia
- Utopia 2030
- Utopia 58
- Utopia Betrayed
- Utopia mit kleinen Fehlern
- Utopia morbida
- UTOPIA, Come nacque il Nuovo Mondo
- Utopian Massacre
- Utopias: The Plague Wars
- Utopic Paradigm