Magic theory is theory on how, and why, magic works.

The question on if it does at all is usually avoided. Magic theory is not an organized science, but best described as an assortment of wildly speculative and often contradictory belief systems; however, there are often common themes and ideas that run through many systems. See magic (paranormal) for a few examples.

Since the advent of chaos magic, it has become fashionable to shift one's magic theory whenever necessary, apparently out of the realization that none of these theories explain the supposed phenomena in full.