Larian Studios Forums Baldur's Gate III Baldur's Gate III - General system question : which ability is linked to a given spell ?

Basically

Cast through technique, learning, and practice, and treating the world like a cosmic rube-goldberg device (Wizards, Artificers, Eldritch Knight, Arcane Trickster) - use Intelligence
Cast through awareness of the self and the world around you on a metaphysical level (Clerics, Rangers, Druids.. some Monks) - use Wisdom
Cast through sheer force of will and inner self-image sufficient to alter reality (Paladin, Sorcerer, Bard, Warlock) - use Charisma

So, Poison Spray cast by Wizard uses Intelligence. Cast by druid uses Wisdom. Cast by Warlock uses Charisma.

If you take the Magic Initiate feat then your casting stat for the associated spells will be based on the named class... so a Wizard with Magic Initiate: Cleric will have a handful of Wisdom-based spells.


Also note that currently wizards being able to cast any spell is probably a bug. Wizards have by far the largest and most diverse spell list of any caster, but there are some spells they generally don't get.