Monad may refer to:
* Monad (Greek philosophy) a term meaning "unit" used variously by ancient philosophers from the Pythagoreans to Plato, Aristotle, and Plotinus to signify a variety of entities from a genus to God.
* Monism, the concept of "one essence" in the metaphysical and theological theory
* Monad (Gnosticism), the most primal aspect of God in Gnosticism
* Monadology, a book of philosophy by Gottfried Leibniz in which monads are a basic unit of perceptual reality
* Monadologia Physica by Immanuel Kant
* The Cup or Monad, a text in the Corpus Hermetica