Fantasy writing Science fiction writing Writing Genres

The difference between fantasy and science fiction

The difference between the fantasy and science fiction genres hasn’t always been an issue. However, there are a few key differences in the genres that can help us to separate one type of book from the other in the ‘science fiction vs fantasy’ debate.

What’s the difference between fantasy and science fiction? There are a few key differences between the genres that are worth thinking about in any ‘science fiction vs fantasy’ debate.

Why do the differences between sci-fi and fantasy matter?

One of the most important reasons to think about these genres differences is book marketing.

Agents and publishers will want you to succinctly describe your book, in terms that make its genre clear.

When it is clear that your book falls into a specific genre (though many ‘science fantasy’ novels blend both), this makes it easier for readers to find it.

In addition, if you want to write a book, your plot will differ according to whether you are using classic fantasy or science fiction themes and tropes.

Science fiction vs fantasy: Key elements

Let’s explore key differences between science fiction and fantasy:

Science fiction tends to focus on technological advancement

Alien civilizations with advanced spacecraft. Humans creating robots that spell their doom. Science fiction most often grapples with the question of technology and its capacity for good and harm.

Science fiction quote - Marion Zimmer Bradley

Sci-fi makes the implausible possible

[Thank you to Sam in the comments for this good phrase – ed’s note.]

Science fiction deals with scenarios and technology that are possible or may be thanks to scientific discovery.

Now Novel writer

Finish your fantasy, together

Work one-on-one with an experienced coach who’ll provide feedback and guidance.


Some science fiction such as far-future space opera or time travel stories may seem implausible, but they are still not beyond the realm of scientific theory.

Fantasy makes the physically impossible real

On the other hand, fantasy generally deals with supernatural and magical occurrences that have no basis in science or (often) even physics.

Fantasy predates science fiction

Fantasy is an older genre of literature than science fiction; in fact, fantasy is arguably the oldest genre.

If we look back at the earliest surviving stories from human civilisation such as the Sumerian Epic of Gilgamesh or the ancient Greek myths, we find stories of gods, monsters and magic.

Science fiction is a relatively recent genre of the last century or so with origins going back only a few hundred years before that.

George R R Martin quote on fantasy

How are science fiction and fantasy alike?

Both fantasy and science fiction entail imagining other possible worlds. They explore hypothetical futures (or pasts).

Both genres require rules. Just because fantasy is not based on scientific facts or speculation doesn’t mean that anything goes in fantasy. Certain laws must govern a fantasy world as well; the difference is that in fantasy, the author makes up the rules.

In sci-fi, the author may make up some of the world’s rules, but these are often drawn from taking scientific realities (such as AI or the search for new technological abilities) to new conclusions.

Surprisingly, science fiction and fantasy cannot always be distinguished by settings or other elements. Many would argue that Anne McCaffrey’s Pern series is science fiction despite the existence of dragons while others say the Star Wars films are clearly fantasy despite the space setting.

For a deeper dive into fantasy fiction, this complete guide shares popular subgenres, worldbuilding tips, fantasy-writing tips from masters of the genre and more.

Have a fantasy or science fiction book in progress? Work with a writing coach who understands your genre.

Working with a coach has helped me stay focused and purposeful in my writing sessions, and I’m near the end of my first draft now. The continuous encouragement has helped so much and I have the guides on Now Novel’s blog to dip into whenever a craft-related problem crops up, as well as my coach – a great sounding board. — James

Read more reviews on:


By Bridget McNulty

Bridget McNulty is a published author, content strategist, writer, editor and speaker. She is the co-founder of two non-profits: Sweet Life Diabetes Community, South Africa's largest online diabetes community, and the Diabetes Alliance, a coalition of all the organisations working in diabetes in South Africa. She is also the co-founder of Now Novel: an online novel-writing course where she coaches aspiring writers to start - and finish! - their novels. Bridget believes in the power of storytelling to create meaningful change.

34 replies on “The difference between fantasy and science fiction”

You’ve identified the major criteria that has been used as the dividing line between the two genres; it’s the one we’ve pretty much all been using from the beginning of whenever it became necessary to make such distinctions.
Two follow-ons. First – I think there does have to be some weight given to the author’s intention: what were they trying to right? A “science fiction” novel written by someone not well-versed in science may very well cross the plausibility line. And of course we always have to make room for the science fiction story that pays more attention to the trappings and tropes than it does actual science (many comic book stories, for example); there’s no way one can say that Flash Gordon isn’t science fiction, but…
Second, there is of course the problem presented by Clarke’s dictum of ‘any sufficiently advanced technology will appear as magic’ always hovering in the background. One could excuse almost anything by citing “sufficiently advanced technologies” and again the plausibility argument fails us here – which kind of brings us back to intention.

When it comes to specifying the genre of your book, does that mean you cannot have a combination, like say science fiction and fantasy or whatever? Sorry, just curious about that.

Hi Nana – you definitely can. Authors such as Ursula K. Le Guin often have. Break all the rules, besides, if it helps you a better and more engaging story.

Perhaps you can. But then geeks will have *really* strong arguments whether this book is “true” science-fiction or fantasy or not. In other words: a Pandora’s box 🙂

The year I was born, the ‘Flip Phone’ only existed on a new TV show call “Star Trek”. Now, when I need to get a new phone, I buy a cover with a texture that I think will hold the painted words, “DON’T PANIC!”, in big, friendly letters. I’ll leave it to you to decide where to draw any lines you may feel the need to draw.

” Science fiction is a relatively recent genre of the last century or so with origins going back only a few hundred years before that.”

The origins of science fiction are actually almost a couple of thousand years old- this is ‘A True Story’, a Greek science fiction story about an interplanetary war written in the second century CE.

Great argument, Dave, thank you for sharing this counter-view. It’s much the same as many arguing Don Quixote was the first novel. I suppose when we refer to modern science fiction’s boom, it really took off after industrialization and the various possibilities steam power unlocked in writers’ imaginations. Thank you for sharing your perspective.

This describes fairly accurately the commonly held view on the topic. However, it does have built into it an understanding which is not commonly shared… That is, to write good science fiction requires a good understanding of science in the first place.

In my humble opinion, most science fiction fails on this simple point, and it does so because the majority of new SF is a slight variation of previous themes. It almost gives a tacit vindication of breaking the laws of physics if a previous SF book has done so.

For example a common theme involves space travel at super luminal velocities. Yet without some explanation as to how this violation can occur, this detail alone renders the book a fantasy rather than pure SF.

So dear reader, I caution – know thy science to write good SF, or be honest and call it science fantasy. Let us return science fiction to a land of true exploration based on the known laws of physics. However, I suspect this will strip many existing books of this categorisation but will make the genre exciting once more.

This post was truly worthwhile to read. I wanted to say thank you for the key points you have pointed out as they are enlightening.
Fantasies are more than dreams. They are shared imaginary images that can either frighten or thrill the readers of the fantasies.
Check my blog about Fantasy Writing
Hope this will also help. Thank you.

It’s really fairly simple folks and I’ll put it in a nutshell: science fantasy makes the impossible, possible. Science fiction on the other hand, makes the improbable plausible. Granted there are gray areas between the two genres.

Hi Sam, thank you for sharing that! It’s an interesting take (although maybe I’d add that science fiction or speculative fiction more broadly also makes the probable/likely actual?) For example, we have people like Elon Musk wanting to put chips in people’s brains, so a cyborg isn’t too far off of reality nowadays (i.e. whether or not it’s possible is an increasingly gray area too). Thank you for sharing your thoughts.

What about giving a fantasy element a scientific origin in your story world?
For example, mythological creatures like dragons, chimeras, griffins,… are definitely a fantasy element. But if a fantasy element like that gets a scientific origin like genetic engineering, or as part of a technologically advanced society’s terraforming process, can you still call it a fantasy element or has it become science fiction?

That’s a great question, Jolene. I would say if technological experimentation or ‘progress’ features then there is a definite science fiction element. Many authors do write science fiction with fantasy elements (or fantasy with science fiction elements) so you could probably market the book under both categories due to this hybrid genre element.

Science fiction imagines ‘probable’ worlds often (where, for example, X technological idea such as artificial intelligence is taken to a further conclusion) and fantasy imagines ‘possible’ or even impossible worlds (thinking here, for example, of Terry Pratchett’s flat world balanced on the backs of four elephants which in turn stand on the back of a giant turtle). So if a story combines both things it’s more of a hybrid genre.

Let me know if you have any further questions, and thank you for reading our blog.

Science-fiction stories have significantly changed the world. Most of the technologies people rely on today were built from science-fiction novels, magazines, or movies. They have caused scientific developments and provided visions that inspired scientists and engineers to create for generations.

I love that idea, Benoit – it’s true that sci-fi has ‘predicted’ (or rather influenced) ways we think about and use technology. That’s a very interesting thought, thank you for reading our blog and for sharing.

The Orson Scott Card Ender’s books are a good example of a cross over between sci-fi and fantasy. There are definitely sci fi elements in the earlier books but the series skews towards fantasy when physics is supplemented by magic.

Thank you for sharing this, James – that is a good example (though it is unfortunate in my opinion that Scott punches down at minorities in some of his work, so there are other authors I would recommend over OSC). For example McCaffrey’s ‘Dragonriders of Pern’ series.

Hi Michael, thanks for asking. [Salon has a fairly detailed write-up]( of some of Scott Card’s documented anti-LGBTQ+ statements as well as propagandistic elements of his fiction. Of course if a person is of a conservative point of view they might not see this as punching down, but I would say taking aim at LGBTQI+ people is punching down, this group being a vulnerable minority in every country. I hope this clarifies what I meant, please feel free to disagree.

Leave a Reply

Your email address will not be published. Required fields are marked *