Tralfamadore is the name of a fictional planet appearing in the novels of Kurt Vonnegut in inconsistently described variations. It is variously depicted as being located outside of the Milky Way galaxy<!--"several galaxies away"--> or being fictional within the fiction itself. A central plot revolves around a Tralfamadorian messenger "stranded on Titan" who takes "control of human history in order to transmit a message home requesting a spare part for his spaceship."
- In the 1969 novel Slaughterhouse-Five, Tralfamadore is the home to organic beings who can see into all times, and are thus privy to knowledge of future events. Lawrence R. Broer described both them and their counterparts from Sirens as "ludicrous-looking". Science-fiction scholar Brian Stableford suggested that Tralfamadore here exists in a different fictional universe than the planet referred to in Sirens of Titan, but where the original organic inhabitants have not died out. In a similar role to God Bless You, Mr. Rosewater, Tralfamadore for Pilgrim is a place "where the problematic aspects of his earthly existence are all nicely resolved.".
- In the 1990 book Hocus Pocus, Tralfamadore appears again in a fiction within the fiction, published in a pornographic magazine. As in The Sirens of Titan, the Tralfamadorians disrupt the history of humankind, here in favor of bacteria which they view as more valuable. Salman Rushdie remarked that this has the effect that "it makes a person feel pretty darn small". considering them a "peerlessly cruel and oafish species".
A recurring characteristic of the inhabitants of Tralfamadore is their low esteem of humanity.