Dualism most commonly refers to:

• Mind–body dualism, a philosophical view which holds that mental phenomena are, at least in certain respects, not physical phenomena, or that the mind and the body are distinct and separable from one another
  • Property dualism, a view in the philosophy of mind and metaphysics which holds that, although the world is composed of just one kind of substance—the physical kind—there exist two distinct kinds of properties: physical properties and mental properties
• Cosmological dualism, the theological or spiritual view that there are only two fundamental concepts, such as "good" and "evil", and that these two concepts are in every way opposed to one another

Dualism may also refer to:

• Dualism (cybernetics), systems or problems in which an intelligent adversary attempts to exploit the weaknesses of the investigator
• Dualism (Indian philosophy), the belief held by certain schools of Indian philosophy that reality is fundamentally composed of two parts
• Dualism (politics), the separation of powers between the cabinet and parliament
• Dualism in medieval politics, opposition to hierocracy (medieval)
• Epistemological dualism, the epistemological question of whether the world we see around us is the real world itself or merely an internal perceptual copy of that world generated by neural processes in our brain
• Ethical dualism, the attribution of good solely to one group of people and evil to another
• Monism and dualism in international law, a principle in contending that international and domestic law are distinct systems of law, and that international law only applies to the extent that it does not conflict with domestic law
• Soul dualism, the belief that a person has two (or more) kinds of souls