Warhammer 40k factions are the armies you collect, build, and paint, and there are a lot of them. This guide explains the three big buckets they fall into and how to pick one that fits how you like to play.
What counts as a faction?
In 40k, a faction is usually a full army with its own rules, models, and a codex or index. That’s the practical definition most players use when they ask what you play.
But you’ll see different numbers floating around. Some lists count only the main armies. Others count big subfactions like Space Marine Chapters or Chaos Legions as separate factions, and that’s why the totals don’t always match.
The safest way to think about it: there are three super-factions (Imperium, Chaos, Xenos), and inside each one you’ll find a bunch of distinct armies.
The three super-factions
The Imperium of Man is humanity’s bloated, paranoid empire. It includes Space Marines, the Astra Militarum (ordinary soldiers), the Adeptus Mechanicus, the Sisters of Battle, the Custodes, and more. They’re the ‘good guys’ only in the loosest sense.
Chaos factions are the Imperium’s dark mirror. Chaos Space Marines, Chaos Daemons, Death Guard, Thousand Sons, World Eaters, and Emperor’s Children all serve the Ruinous Powers, each in their own twisted way.
Xenos covers everyone else: Orks, Aeldari, Drukhari, Necrons, Tyranids, T’au, Genestealer Cults, and Leagues of Votann. They rarely team up with each other, and they don’t care about humanity’s problems.
How to pick your first faction
Start with the look. You’ll spend hours building and painting these models, so pick an army you actually enjoy staring at. Rules change every edition; cool models stay cool.
Then think about playstyle. Do you want a tough elite force (Custodes, Space Marines), a horde (Orks, Tyranids, Astra Militarum), or something tricksy (Aeldari, Genestealer Cults)?
If you’re still stuck, grab a starter set or a combat patrol box for the faction that tempts you most. It’s the cheapest way to try before you commit.
- Imperium: Space Marines, Astra Militarum, Adeptus Mechanicus, Sisters of Battle, Custodes, Imperial Knights, Grey Knights, Imperial Agents
- Chaos: Chaos Space Marines, Chaos Daemons, Death Guard, Thousand Sons, World Eaters, Emperor’s Children, Chaos Knights
- Xenos: Orks, Aeldari, Drukhari, Necrons, Tyranids, Genestealer Cults, T’au Empire, Leagues of Votann
Why it matters for new players
Knowing the factions helps you understand the game’s lore and make a smarter first purchase. It also stops you from buying models that can’t legally team up, since Imperium, Chaos, and Xenos usually don’t mix.
And if you’re just here for the stories, the factions are the cast. Every novel, campaign, and codex spins out of these armies and their endless war.
Key facts
- Warhammer 40k factions are the playable armies of the tabletop game, each with its own models, rules, and lore.
- They’re grouped into three super-factions: Imperium, Chaos, and Xenos.
- Different sources list different numbers because some count major subfactions as separate armies.
- Picking a faction is mostly about which models you enjoy and how you like to play.
- Alliances between super-factions are rare, so your first choice locks you into a style.
FAQ
How many Warhammer 40k factions are there?
It depends on how you count. There are around 20 to 27 main armies with their own codexes, plus minor subfactions that sometimes get their own rules. Most guides stick to the main ones.
Can I mix factions in one army?
Usually no, or only in limited ways. Imperium armies can ally with other Imperium armies, Chaos with Chaos, and Xenos rarely ally with anyone. Your codex will spell out the exact rules.
Which faction is best for beginners?
Space Marines are the classic starting point because they’re forgiving, well-supported, and come in cheap starter sets. But any faction can work if you love the models enough to paint them.