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

The Homing Pigeons, features President Kennedy, although it has very little to do with the President. Near the end of the book it keeps switching universes, some of which contain President Kennedy, others which contain President Lousewort, and still others in which Hubbard is the president. Like The Trick Top Hat, The Homing Pigeons also has material in the Pocket Books edition that is not in later editions. Unlike The Trick Top Hat, however, the material that was cut out did not contain particularly sexually explicit content.