The Schrödinger's Cat Trilogy is a trilogy of novels by American writer Robert Anton Wilson consisting of The Universe Next Door, The Trick Top Hat, and The Homing Pigeons, each illustrating a different interpretation of quantum physics. Wilson is also co-author of The Illuminatus! Trilogy, and Schrödinger's Cat is a sequel of sorts, re-using several of the same characters and carrying on many of the themes of the earlier work.

The one-volume edition currently in print is significantly shorter than the original three-volume edition. This is not a difference in print size or removal of redundant "recaps"; it is missing a noticeable amount of material, including many entire chapters.

The name Schrödinger's Cat comes from a thought experiment in quantum mechanics. The first book, The Universe Next Door, takes place in different universes in accord with the many worlds interpretation of quantum physics; in the second, The Trick Top Hat, characters are unknowingly connected through non-locality, i.e., having once crossed paths they are joined in quantum entanglement; and the third book, The Homing Pigeons, places characters in an "observer-created universe" in which Consciousness Causes the Collapse of the wavefunction.

Taking place in Unistat, which is the novel's parallel to the United States, the novels have intertwining plots involving a wide array of characters, including:

Epicene Wildeblood, a.k.a. Mary Margaret Wildeblood, a transsexual woman who throws great parties
Frank Dashwood, president of Orgasm Research
Markoff Chaney, a prankster
Hugh Crane, a.k.a. Cagliostro the Great, a mystic and magician
Furbish Lousewart V, author and President of Unistat
Marvin Gardens, author and cocaine addict
Eve Hubbard, scientist and alternate President of Unistat

In The Trick Top Hat, President Hubbard, promotes a scientific approach to the improvement of life: she offers rewards to anyone who can design a robot to do their job or develop methods to prolong life. Eventually Unistat becomes a Utopia. She makes the whole law system into three different laws: victimless crimes, which have no punishment; crimes against property, which involve debt and payment; and serious crimes, such as murder, which result in being sent to Hell, a place like jail but not quite. It's encased in laser shielding and is like a primitive world all its own. It is, in fact, the State of Mississippi. The original Pocket Books edition of The Trick Top Hat contains many passages, some sexually explicit, that are not included in later editions, including the Dell softcover. Much of this material first appeared in Wilson's earlier novel, The Sex Magicians, published as pornography by Sheffield House in 1973.