Undertale Fanfiction
A child falls into the Underground, a world of monsters, and must find their way back to the surface.
Start Reading Undertale Fanfiction
Explore 95,000 Undertale stories on Archive of Our Own, sorted by popularity. Then enjoy the best reading experience with Fanfict Reader.
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What is Undertale fanfiction?
Undertale fanfiction is fan-created stories set in the Undertale universe. With over 95,000 works on Archive of Our Own, Undertale is one of the most popular fandoms in the fanfiction community.
These stories explore beloved characters like Sans, Papyrus, Frisk, Toriel, and many more. Writers create everything from short one-shots to epic novel-length adventures, exploring relationships, alternate universes, and "what if" scenarios.
Most Popular Undertale Fanfics
These are the highest-rated Undertale stories on AO3, ranked by kudos from readers.
A Totally Fantastic Guide To Vigilantism
by Apathetic_Blossom
The world has always dealt in absolutes. It was absolute when it took Error's parents away from him, leaving behind three siblings with nothing but each other to rely on. It was absolute when it coaxed him to become something greater than himself, fueled by the pain and desire to right society's wro
Through Infected Worlds
by M3atBall_Sub
The Rogues never considered the consequences of crossing so many different realities, each with its own unique viruses and infections. When the viruses inevitably come across one another, they fuse into a single, larger virus, or super-virus. What results from this tiny oversight is the destruction—
White Water
by Kinomi_Not_Kuromi
You woke up in a world full of cold tile and water, there are unique rooms of course, but all of the sunlight is false, there is no outdoors, just buzzing headlights and sudden darkness. You can’t die here, even when you want to you wake up again. You don’t know how long it’s been, years? Days? It’s
asriel dreemurr is a FREAK
by EVIL FART SMELLA 287 (fartsmella287)
asriel is an idiot that's why he gets up late at 11 am because he was masturbating thinking about chara even though they were right next to him (i just made all that up) but being the idiot he is he forgets it's Sundayyyyyy and theres no job so they can FUCK!!!!
A New Sprout
by Anonymous
After battling a god-like being, the golden flowers planted a new fear in the monsters' hearts. The barrier shattered, and the monsters brought wounded human children to the city for treatment, discussing the kingdom's future. Just as the short skeleton intended to remain uninvolved as always, he en
Popular Undertale Ships
Sans/Reader
Sans/Reader
The laid-back skeleton Sans paired with the reader insert, allowing fans to explore a personal relationship with the popular character.
55,000 works →
Sans/Frisk
Sans/Frisk
The skeleton Sans and the human child Frisk, typically aged up in fanfiction to explore their connection across timelines and resets.
30,000 works →
Papyrus/Reader
Papyrus/Reader
The enthusiastic skeleton Papyrus paired with reader insert, focusing on his boundless optimism and genuine kindness.
25,000 works →
Alphyne
Alphys/Undyne
The anxious scientist Alphys and the fierce warrior Undyne, whose opposites-attract dynamic is canon in the game.
20,000 works →
Soriel
Sans/Toriel
The skeleton Sans and goat monster Toriel, who bond over puns and their shared care for others, especially Frisk.
18,000 works →
Common Undertale Tropes
Popular Characters
Frequently Asked Questions
How many Undertale fanfics are on AO3?
There are over 95,000 Undertale fanfiction works on Archive of Our Own, making it one of the platform's largest fandoms.
What are the best Undertale ships?
Popular Undertale pairings include Sans/Reader, Sans/Frisk, Papyrus/Reader. Each ship has thousands of dedicated stories exploring their relationship.
How can I read Undertale fanfiction on my phone?
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