Schools of magic are groups of related spells that work in similar ways. A Wizard may choose to specialize in a school of magic and therefore gains one additional prepared spell per level but loses the ability to cast spells from one other opposed school. Specialist wizards are granted a bonus in identifying spells from their area of expertise and a penalty in identifying spells from the opposing school. A wizard may choose not to specialise in a particular school of magic and thus is able to use them all but without any bonuses.

The default schools of opposition, as set up by BioWare, are different from PnP due to the limited selection of spells available in NWN for some schools. These defaults are as follows:

• Abjuration - opposed by Conjuration
• Conjuration - opposed by Transmutation
• Divination - opposed by Illusion
• Enchantment - opposed by Illusion
• Evocation - opposed by Conjuration
• Illusion - opposed by Enchantment
• Necromancy - opposed by Divination
• Transmutation - opposed by Conjuration

In a purely Roleplaying Persistent World, the choice of school (or the lack of school) should be determined by the character's background mainly. For example, a character with a background that includes Velsharoon would be a natural choice for the Necromancy school of magic.