How Do You Unlock More Weapon Slots in Borderlands 2?

In Borderlands 2, there are a total of 57 weapon slots. However, you only start out with two weapon slots unlocked.

The remaining 55 must be unlocked through various means.

The first way to unlock additional weapon slots is by completing missions. Some missions will reward you with an additional weapon slot upon completion.

These missions are usually side missions, and not the main story missions.

Another way to unlock weapon slots is by purchasing them from Marcus the gun salesman. He can be found in Sanctuary, and will sell you additional weapon slots for 25,000 cash each.

Lastly, you can also unlock weapon slots by completing challenges. There are many different challenges in Borderlands 2, and each one completed will give you a small amount of progress towards unlocking an additional weapon slot.

The challenges range from simple things like killing a certain number of enemies, to more difficult tasks like finishing the game on True Vault Hunter mode.

So those are three ways to unlock additional weapon slots in Borderlands 2. By completing missions, buying them from Marcus, or completing challenges, you can slowly but surely work your way up to having all 57 weapon slots unlocked.