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